- Email: [email protected]
Lesions of the thoracic aorta and its arch branches simulating neoplasm
J THoRAc CARDIOVASC SURG 81:251-263, 1981
Lesions of the thoracic aorta and its arch branches simulating neoplasm Abnormal radiographic densities in the midportion of the chest are most commonly caused by neoplasms, cysts, or inflammatory disease. However, vascular lesions may present an identical x-ray appearance, with no distinguishing clinical history or physical findings. The cardiothoracic surgeon must be aware of this similarity in order to ensure the most appropriate diagnostic and therapeutic approach. In our experience, the most frequent problem in differential diagnosis is a lesion of the thoracic aorta or its arch branches simulating neoplasm. Nine such cases are presented, with pertinent conventional radiographs, angiograms, and computed tomographic iC'T} scans. These are considered in anatomic sequence: (I) ruptured sinus of Valsalva aneurysm; (2) ascending aortic aneurysm; (3) tortuosity or aneurysm of the innominate and subclavian arteries; (4) transverse arch aneurysm; (5) pseudocoarctation; and (6) descending aortic aneurysm. Such vascular lesions must be considered early in the evaluation of any juxta-aortic chest density, particularly if the patient is hypertensive and has other manifestations of atherosclerosis. Angiography and computed tomography establish the diagnosis in most instances, although both are less reliable when thrombus fills all or part of an aneurysm. If these methods fail to establish a vascular orgin, the possibility of neoplasm is pursued. When neither a vascular nor neoplastic origin can be proved, surgical exploration is indicated in the otherwise good-risk patient.
David M. Shahian, M.D., Hushang Javid, M.D., Ph.D., L. Penfield Faber, M.D., C. Frederick Kittle, M.D., and Guy R. Matthew, M.D., Chicago, Ill.
Tortuosity and aneurysm of the thoracic aorta and its arch branches are common, particularly in elderly patients with hypertension and diffuse atherosclerosis. They appear radiographically as densities in the midportion of the chest and may be indistinguishable from cystic, inflammatory, or neoplastic disease. The history, clinical symptoms, and physical examination may also fail to differentiate between these entities. Inaccurate assessment by the thoracic surgeon may lead to exploration and discovery of an unsuspected vascular lesion for which no therapy is required or whose therapy requires different exposure or facilities than those available. Conversely, if a pulmonary neoplasm is misinterpreted as a benign vascular anomaly, the opportunity for early cure is lost. In an effort to emphasize this problem in differential
From the Departments of Cardiovascular-Thoracic Surgery and Radiology, Rush-Presbyterian-St. Luke'sMedical Center, 1753 West Congress Parkway, Chicago, Ill. Received for publication May 14, 1980. Accepted for publication June 9, 1980. Address for reprints: Hushang Javid, M.D., 1753 West Congress Parkway, Chicago, Ill. 60612.
diagnosis, we have selected the following cases from our own experience. These lesions of the thoracic aorta and its arch branches, all initially misinterpreted as neoplasms, are presented in anatomic sequence from the sinuses of Valsalva to the descending thoracic aorta (Fig. 1).
Case presentations Ruptured sinus of Valsalva aneurysm.
CASE 1. A 55-year-old man had a history of mild hypertension and presented to the emergency ward with atypical chest pain suggestive of a myocardial infarction. Physical examination revealed only a Grade 2/6 systolic ejection murmur along the sternal border. Chest roentgenogram demonstrated a large mass in the right anterior mediastinum (Fig. 2, A), thought to be neoplastic. After serial electrocardiograms and cardiac enzymes had ruled out an infarction, the patient was transferred to the thoracic surgery service. Exploration was performed through a right thoracotomy with a preoperative diagnosis of mediastinal neoplasm, probably thymoma or teratoma. There was a 9 by 9 cm mass arising from the right ventricle and the base of the ascending aorta. This mass was quite firm and was thought by some observers to be a cardiac tumor. However, the possibility of a ruptured sinus of Valsalva aneurysm was also considered, and further intervention was deferred. Postoperative angiography revealed a clot-filled sinus of Valsalva aneurysm with rupture into the right ventricle (Fig. 2, B).
0022-5223/81/020251 + 13$01.30/0 © 1981 The C. V. Mosby Co.
251
The Journal of
252 Shahian et al.
Thoracic and Cardiovascular Surgery
Aberrant R. Subclavian Aneurysm
Trans. Arch Aneurysm
Pseudocoarctation
Ruptured Sinus 01 Valsalva Aneurysm
Fig. 1. Lesions of the thoracic aorta and arch branches which may simulate neoplasm. Comment. Nonruptured sinus of Valsalva aneurysms are usually undetected unless angiography is performed for an associated cardiac defect. Those that have ruptured have a clinical spectrum ranging from asymptomatic to the classic presentation of acute chest or upper abdominal pain, heart failure, continuous murmur, and widened pulse pressure. Often the development of dyspnea, fatigue, and/or orthopnea is gradual. Chest pain may be only a transient phenomenon. The chest radiograph in unruptured aneurysm may be normal or may demonstrate a convexity at the base of the aorta, which forms a double contour along the right atrial border. Ruptured aneurysms may show cardiomegaly and increased pulmonary vascular markings. Our patient's presentation was quite unusual, with rupture into the right ventricle producing the radiographic and operative appearance of a neoplasm. Harris' described a similar case in which the aneurysmal wall contained calcium, further complicating the differential diagnosis. Ascending aortic aneurysm. CAS E 2. A 61-year-old woman had a past history of hypertension, adult onset diabetes, and tobacco abuse. She presented to her physician with cough, hemoptysis, and bilateral anterior chest pain. Posteroanterior and lateral chest x-ray roentgenograms (Fig. 3, A and B) revealed a mass in the upper left lung field, which on tomography was anterior and appeared separate from the aortic arch. Following a normal bronchoscopic study, the chest was explored through a left thoracotomy with a preoperative diagnosis of cancer. A large saccular aneurysm of the ascending aorta was discovered,
and the procedure was terminated. Postoperative aortography confirmed a clot-filled saccular aneurysm of the ascending aorta. The patient declined re-exploration and resection. Rupture of the aneurysm into the left side of the chest resulted in the patient's death 5 years later.
Comment. Aneurysms of the ascending aorta may result from atherosclerosis, syphilis, or Marfan's disease with annuloaortic ectasia. Except in the third instance, in which there is associated aortic insufficiency, early symptoms may be minimal or absent and the lesion may be discovered on a routine chest x-ray film. Erosion of the sternum or ribs and obstruction of the superior vena cava are late findings. In the typical fusiform ascending aneurysm, the classic radiographic finding is a mass projecting beyond the right heart border, such that a tangent drawn perpendicular to the margin falls lateral to the right atrial border. 2 The right heart border may be obscured on posteroanterior films, since both it and the aneurysm are anterior structures. Our patient's presentation was exceedingly unusual, with a large, saccular aneurysm of the ascending aorta projecting into the left side of the chest. The symptoms and plain radiographic appearance were indistinguishable from bronchogenic carcinoma. Transverse arch aneurysm.
CAS E 3. Three weeks prior to admission to our institution, a 79-year-old physician had been hospitalized elsewhere for treatment of a fractured hip. Routine chest roentgenogram revealed a 4 by 4 cm mass in the left suprahilar region (Fig. 4, A). The patient was normotensive and had a 20 pack-year smoking history. Other than chronic hoarseness, there were no signs of pulmonary or systemic illness. Tomography suggested bronchogenic carcinoma, although bronchoscopy revealed no endobronchial lesions. Computed tomographic (CT) scans revealed this mass to be between the inferior portion of the transverse arch and the superior portion of the pulmonary artery (Fig. 4, B). It could not be separated from these vascular structures, although on infusion it did not enhance. Because of these equivocal findings, aortography was performed. This study showed a saccular aneurysm of the inferior portion of the transverse arch, oriented toward the left (Fig. 4, C and D). In view of the patient's advanced age, absence of symptoms, and the small size of the aneurysm, surgical correction was deferred. CAS E 4. A 72-year-old woman presented with the recent onset of hoarseness and a 25 pound weight loss. She had a 30 pack-year smoking history, hypertension, and diabetes. Her son had died of oat cell carcinoma several years previously. Results of physical examination were normal, except for a left vocal cord paralysis. Chest x-ray film revealed a 2 by 3.5 em left hilar mass adjacent to the mid-transverse thoracic aorta (Fig. 5 A). Bronchoscopy and metastatic work-up showed no abnormalities. Aortography revealed severe atherosclerosis with irregularity of the infralateral portion of the transverse arch, thought to be diagnostic of a clot-filled aneurysm (Fig. 5, B and C). Exploration was declined by the patient. She died suddenly at home 4 months later.
Volume 81 Number 2
Vascular lesions simulating neoplasm
253
February, 1981
Fig. 2. A, Large mass of right anterior mediastinum in a 55-year-oldman with atypical chest pain. B, Angiography reveals a sinus of Valsalva aneurysm (arrow) with rupture into the right ventricle.
Fig. 3. Posteroanterior (A) and lateral (B) chest roentgenograms of an elderly womanwith a mass in the left upper
lung field. Exploration was performed, with a presumptive diagnosis of cancer. A large saccularaneurysmof the ascending aorta was found, with atypical presentation in the left side of the chest.
Comment. Aneurysms of the transverse arch are uncommon and may result from atherosclerosis, trauma, or dissection. Crawford, Saleh, and Schuessler recently have described their surgical experience with 30 such cases. These aneurysms may be fusiform or saccular, and most often they arise in the distal portion of the arch near the left subclavian artery. Because of their location near the narrow thoracic inlet and their close proximity to the trachea, esophagus, superior vena cava, and left recurrent laryngeal and phrenic nerves,
symptoms may be present even when the aneurysm is relatively small. These include cough, chest pain, airway obstruction, dysphagia, hemoptysis or hematernesis, and hoarseness. The aortic pulsation may be palpated through the chest wall in some instances. Characteristic radiographic findings include elongation of the aortic knob, right and posterior displacement of the trachea and esophagus, and downward displacement of the left bronchus. However, Wixson, Baltaxe, and SOS4 have recently reviewed the problems which
The Journal of
254 Shahian et al.
Thoracic and Cardiovascular Surgery
Fig. 4. A, A 79-year-old man with an asymptomatic left suprahilar mass (arrow). Tomography suggested bronchogenic carcinoma, but bronchoscopy showed no abnormality. B, Computed tomographic scan shows contiguity between the mass (arrow) and the transverse arch, but there was no enhancement with dye infusion. C and D. Arteriography revealed a saccular aneurysm of the inferior portion of the transverse arch (arrows).
can occur in making this diagnosis from radiographs. Often there is no calcification in the rim of the aneurysm, and the main body of the mass may appear separate from the aorta. Noncalcified aneurysms of the inferior arch may not be seen at all on plain x-ray films, their presence suggested only by obstructive sequelae. Finally, the aortic knob silhouette may be normal if a
transverse arch aneurysm arises anteriorly, and the true nature of the lesion may not be appreciated. A high index of suspicion for any lesion near the aortic knob is the first step in accurate diagnosis. Angiography usually demonstrates the aneurysm, although the presence of clot may result in underestimation of its size. Occasionally only the neck of the aneurysm may
Volume 81 Number 2
Vascular lesions simulating neoplasm
255
February, 1981
be demonstrated, seen as an irregular border of the transverse arch. CT scans may better show the size and configuration of the aneurysm. However, if clot-filled, the aneurysm may not enhance with infusion, and the differentiation from neoplasm may still be uncertain. Innominate-subclavian artery tortuosity and aneurysm. 5. A 61-year-old woman was a one pack per day smoker with a history of hypertension, chronic renal failure, and scoliosis; she had no pulmonary symptoms. She was admitted for evaluation of peripheral neuropathy and was found on roentgenography to have a mass at the right lung apex (Fig. 6, A). Comparison with old films demonstrated enlargement of this area during the previous year, and pulmonary neoplasm was considered the most likely diagnosis. However, because a prominent right supraclavicular subclavian pulsation was noted, vascular origin of the mass was also considered. Aortography was performed as the final preoperative study. This demonstrated a tortuous, kinked right subclavian artery which, in combination with the patient's scoliosis, resulted in the abnormal right apical density (Fig. 6, B). CASE 6. A 73-year-old woman was a nonsmoker, in good health except for chronic hypertension. She was referred because of an asymptomatic 2 by 7 ern mass in the right superior mediastinum (Fig. 7, A). Because of its characteristic location and smooth convex border, a vascular lesion was also considered. Tomography revealed an anterior mass arising at the level of the aortic arch (Fig. 7, B) and a contiguous mass posteriorly (Fig. 7, C). Angiography confirmed tortuous, aneurysmal innominate and subclavian arteries (Fig. 7, D). CT scan demonstrated the anterior vascular lesion and the adjacent posterior mass, which did not enhance with infusion (Fig. 7, E). Although a coexisting pulmonary mass could not be excluded, it was felt that this represented a posterior, clot-filled extension of the innominate aneurysm. The patient declined any further diagnostic or therapeutic intervention. CAS E 7. A 68-year-old man presented to an outside hospital with dysphagia and a density in the right posterosuperior part of the chest on roentgenography (Fig. 8, A and B). He underwent right thoracotomy with a preoperative diagnosis of neoplasm, and an aneurysm of the right subclavian artery was found. It was impossible to obtain control of this vessel, however, and the procedure was terminated. Following transfer to our institution, arteriography demonstrated an aneurysm of an aberrant right subclavian artery (Fig. 8, C and D). Surgical correction was undertaken through a left thoracotomy. CASE
Comment. The innominate artery is fixed between its origin at the aorta and its bifurcation into the carotid and subclavian arteries. Normally, the entire artery and its bifurcation lie well within the right superior mediastinal shadow, formed by the innominate vein and the superior vena cava. With age, chronic hypertension, and generalized atherosclerosis, the innominate artery may undergo elongation, tortuosity, and/or kinking. 5 This appears radiographically as an anterior, convex density arising at the level of the aortic arch. 6 A useful roentgenographic sign is the absence of a distinct bor-
Fig. SA. Roentgenogram of a 72-year-old woman with hypertension and a 30 pack-year smoking history. Her son had died of oat cell cancer several years earlier, and she presented with hoarseness and a 25 pound weight loss. The chest x-ray film reveals a 2 by 3.5 em left hilar mass (arrow) adjacent to the mid- transverse thoracic aorta.
der superiorly. This results from the loss of lung-vessel interface as the artery ascends toward the thoracic outlet. Calcium may be present in the wall. This is not an uncommon lesion, with a significant incidence reported by Honig, Dubilier, and Steinberg? in an angiographic study of hypertensive patients with atherosclerosis. Such a density has been misinterpreted as a mediastinal or right upper lobe lesion. These are most commonly asymptomatic, discovered on routine chest x-ray films in elderly hypertensive patients. 8 Tracheoesophageal symptoms or venous compression infrequently occur. Cerebral vascular symptoms secondary to looped innominate artery are rare, as is Homer's syndrome. Occasionally, a prominent supraclavicular pulsation or bruit may be present. As emphasized by Thomas," the lesion itself is benign and has an excellent prognosis without therapy. It is most important to avoid hazardous and unnecessary invasive techniques such as mediastinoscopy or large cutting needle biopsy. Angiography and CT scanning are usually diagnostic. The diagnosis must be established with absolute certainty before a decision is made to observe such a lesion, so as not to ignore an actual neoplasm and thus lose the opportunity for effective therapy. True atherosclerotic aneurysms of the innominate artery are uncommon compared to tortuosity and buckling." Schumacher and Wright,IO reviewing the English
The Journal of
256 Shahian et al.
Thoracic and Cardiovascular Surgery
Fig. S. Coot'd. Following a negative evaluation for neoplasm, anteroposterior (B) and lateral (C) arteriograms were performed. These demonstrated severe atherosclerosis of the inferolateral transverse arch with irregularity of the border and several small aneurysms (arrows). This was thought to represent the neck of a larger, thrombus-filled aneurysm.
Fig. 6. A. Roentgenogram of a 61-year-old woman with peripheral neuropathy and a mass (arrow) at the right lung apex. B. Aortography reveals a tortuous, kinked right subclavian artery (arrow). Its radiographic appearance is accentuated by the patient's mild scoliosis.
Volume 81 Number 2
Vascular lesions simulating neoplasm
February, 1981
Fig. 7. A, Roentgenogram of a 73-year-old hypertensive woman with an asymptomatic right superior mediastinal mass. B. Tomography reveals a convex anterior mass arising at the level of the aortic arch. The fact that the superior margin is less distinct suggests its vascular origin (see text). C. Additional tomographic sections demonstrate a second, posterior mass. D. Angiography confirms the presence of innominate-subclavian tortuosity and aneurysm.
257
258
The Journal of Thoracic and Cardiovascular
Shahian et al.
Surgery
Fig. 7E. Computed tomographic scan demonstrates both the aneurysm anteriorly and the posterior density seen on regular tomography. Although a coexisting neoplasm could not be excluded, it was felt that this represented a clot-filled nonopacifying portion of the aneurysm. language literature, collected 47 case reports of patients who had undergone operation for a nontraumatic innominate aneurysm. Most such patients present with an asymptomatic right superior mediastinal mass. However, because such aneurysms represent a larger mass within the relative confinement of the superior mediastinum, the range of symptoms is broader than that seen with simple tortuosity. These may include dysphagia, hoarseness, Horner's syndrome, supraclavicular pain, brachial plexus dysfunction with pain or weakness, and upper extremity edema. Cerebral vascular symptoms may result from embolized debris or from associated stenosis. Physical findings, if present, include prominent suprasternal or supraclavicular pulsation and evidence of central venous compression. Angiography and CT scans are the most valuable diagnostic techniques. Aberrant right subclavian artery is the most common congenital anomaly of the aortic arch. II The origin of the artery is at or just distal to the left subclavian, and it most commonly courses in a superior and rightward direction behind the esophagus. Aneurysms of the innominate and subclavian arteries are rare, and aneurysms of an aberrant right subclavian artery are exceedingly uncommon. Hunter and associates'> have described their experience with three such patients, only two cases having been previously reported in the literature. The most common presentation is an asymptomatic right superior mediastinal mass. Dysphagia may occur with increasing size of the aneurysm. Such lesions have been mistaken for neoplasm and for innominate aneurysm. However, a barium esophagogram
reveals the characteristic anterior displacement of the dorsal aspect of the esophagus, at or just above the level of the arch and extending cephalad and to the right. An aortogram with frontal, lateral, and oblique projections confirms the diagnosis. Accurate preoperative diagnosis is particularly important in this lesion. The radiographic appearance may lead to an innappropriate surgical approach through a right thoracotomy, which would make proximal control of the aneurysm impossible and necessitate a second procedure. Pseudocoarctation. 8. A 34-year-old asymptomatic man was referred becauseof an abnormal chest x-ray film. Routine radiographs were interpreted as showing a mass in the anterior mediastinumjust above the aortic knob (Fig. 9,A). This was felt to be a mediastinal neoplasm or cyst. Vascularorigin of the lesion was thought unlikely, and angiography was not performed. Exploration was carried out through an axillary thoracotomy, and the only finding was a pseudocoarctation of the aorta. Distal perfusion pressure and pulses were excellent, and no therapy was indicated. Postoperative angiography confirmed the pseudocoarctation (Fig. 9, B). CASE
Comment. Pseudocoarctation is an acute kinking or anterior "buckling" (Fig. 9, C) of the thoracic aorta at the level of the ligamentum. The aorta proximal to the kink is elongated and arises higher in the mediastinum than usual. This results from the failure of normal contraction of some arterial segments during embryogenesis.!" This condition is to be distinguished from acquired aortic tortuosity, which occurs in elderly, hypertensive patients with atherosclerosis. Isolated pseudocoarctation produces no symptoms
Volume 81 Number 2
Vascular lesions simulating neoplasm
259
February, 1981
Fig. 8. A, Posteroanterior chest film of a 68-year-old man with dysphagia and a density in the right superior mediastinum (arrow). B, Lateral film demonstrates a mass posterior to the esophagus. Aortography in the anteroposterior (C) and right posterior oblique projections (D) reveals a partially thrombosed aneurysm of an aberrant right subclavian artery. Both common carotid arteries originate from a common trunk. and only rarely is a flow murmur heard. Radiographically, it resembles a left para-aortic mediastinal tumor or lymphoma. However, the apparent aortic knob and adjacent mass are actually both parts of a "buckled" aorta, seen in an atypical relationship to each other. The inferior convexity is usually interpreted
as an aortic knob and the superior one as a mass. However, as demonstrated in Fig. 9, B, the superior density is in reality the knob, the junction between the transverse arch and descending aorta near the origin of the subclavian artery. For this developmental anomaly to be distinguished
The Journal of Thoracic and Cardiovascular Surgery
260 Shahian et ai.
Fig. 9. A. Roentgenogram of an asymptomatic 34-year-old man with a mediastinal mass (arrow) just superior to the aortic knob, thought to be cyst or neoplasm. B. Anteroposterior aortogram demonstrates typical pseudocoarctation. Distal pulses were normal, and there was no rib-notching. absolutely from true coarctation, there must be no pressure differential across it and no collateral vessels. No surgical intervention is required. It must be differentiated from other masses in the left superior mediastinum-true aneurysms, mediastinal cysts, or neoplasms. Arteriography is the method of choice, although CT scans and two-dimensional echocardiography may supplant this more invasive technique. Descending thoracic aneurysm. 9. A 63-year-old white woman with chronic hypertension presented to another institution with a history of pain in the right side of the chest. A chest x-ray film revealed a mass in the right inferoposterior mediastinum (Fig. 10, A). Results of bronchoscopy, mediastinoscopy, and an upper gastrointestinal tract series were normal. The chest was explored through a right thoracotomy, with a preoperative diagnosis of mediastinal neurogenic tumor. An aneurysm of the descending thoracic aorta was found, which could not be resected through this approach. The procedure was terminated, and the woman was referred to the cardiovascular service. Angiography demonstrated that the aneurysm extended just caudad to the diaphragm (Fig. 10, B), and resection and graft replacement were accomplished through a left thoracoabdominal incision. CA S E
Fig. 9C. Lateral aortogram of a similar patient with pseudocoarctation demonstrates acute anterior buckling.
Comment. Nondissecting aneurysms of the descending aorta are most commonly atherosclerotic, the remainder being traumatic or mycotic. These may be fusiform dilatations in a diffusely ectatic aorta or may be localized;':' Most are discovered in asymptomatic patients on routine chest x-ray films. In advanced cases, clinical presentations include back pain, evi-
Volume 81 Number 2
Vascular lesions simulating neoplasm
261
February, 1981
Fig. 10. A. Roentgenogram of a 63-year-old hypertensive woman with chest pain and a mass in the right inferoposterior mediastinum. B, Thoracotomy was performed, and a large descending thoracic aneurysm was discovered. Postoperative angiography shows extension of the aneurysm just caudad to the diaphragm. Marked tortuosity accounts for the atypical presentation in the right side of the chest. dence of vertebral erosion or spinal cord destruction, airway obstruction and atelectasis, or hemoptysis. In their more diffuse form, descending aneurysms project lateral to the left heart border. Esophageal displacement is common, since this structure is contiguous throughout the course of the descending aorta. Localized aneurysms of the descending aorta may appear as a right or left hilar or retrocardiac mass .14 With tortuosity of the descending aorta, the aneurysm may be projected into the right cardiophrenic angle on frontal radiographs and into the posterior mediastinum on lateral views. It may thus appear to be a pulmonary or mediastinal neoplasm. 15
Discussion Abnormal radiographic densities in the midportion of the chest are most commonly found to be inflammatory, cystic, or neoplastic. However, in a study of 782 mediastinal masses, Lyons, Calvy, and Sammons!" found 9% of such lesions to be vascular in origin. Kelley, Mannes, and Ravin'? have divided such vascular densities into four groups: (1) systemic venous system,
(2) pulmonary venous system, (3) pulmonary arterial system, (4) systemic arteries. Many such lesions are congenital or acquired anomalies requiring no specific therapy (azygos or hemiazygos vein enlargement, pulmonary venous varix, persistent left superior vena cava, idiopathic dilatation of the pulmonary trunk). Other more significant congenital cardiovascular lesions include anomalous pulmonary venous return, anomalous left pulmonary artery, and aortic or pulmonary stenosis. These have associated physical findings and clinical course which expedite their correct diagnosis and therapy. In our experience, abnormalities of the thoracic aorta and its arch branches present the most common such problem in differential diagnosis. With the exception of pseudocoarctation, these lesions are distinguished by their initial discovery in older patients with hypertension and atherosclerosis; they are often difficult to distinguish from neoplasms. Use of an inappropriate diagnostic technique such as cutting needle biopsy or mediastinoscopy may be fatal in such patients, and failure to establish the correct diagnosis may prevent or
262
The Journal of Thoracic and Cardiovascular Surgery
Shahian et al.
delay the treatment of either a vascular or neoplastic lesion. A lesion of the thoracic aorta or major arch branch should be considered early in the evaluation of any juxta-aortic mass. Plain radiographic features are variable and rarely diagnostic. Likewise, the clinical symptoms of patients with neoplastic and vascular lesions may overlap significantly. Presentations range from totally asymptomatic to vocal cord paralysis, cough, hemoptysis, chest pain, bronchial compression with atelectasis or stridor, or dysphagia. Physical findings suggestive of a vascular origin include severe chronic hypertension, a pulsating mass at the base of the neck, a prominent aortic pulsation in the anterior chest, or a bruit from a kinked vessel. Prior to the late 1940s many central chest densities were merely observed or were irradiated empirically, because they were considered to be unresectable neoplasms. With the advent of angiography and cardiovascular surgery, great interest developed in defining those masses which were vascular in origin. Most older methods of distinguishing vascular from nonvascular lesions-e.g., calcification or the presence of pulsation at fluoroscopy-fell into disrepute. Numerous investigators reported the diagnostic superiority of angiography.1R-23 With increasing experience, it has become apparent that even this method is not infallible. A thrombus-filled aneurysm might not visualize at all or might be only suggested by an irregular aortic border. Wixson," SOS,24 and their associates have recently emphasized this diagnostic problem, and Sprayregen and Jacobson" have enumerated several useful signs in interpreting thoracic aortograms. On the basis of their experience, the more subtle radiographic findings of thoracic aneurysms include slight widening of the aortic lumen, aortic wall thickening, small ulcerlike collections of contrast (border irregularity and spiculation), and local nonopacification of intercostal arteries. They also call attention to the frequent association with abdominal aneurysms. CT scanning, especially with dye enhancement, is a useful new tool with which to image the thoracic aorta'" and other mediastinal masses.F It can at least characterize the extent and localization of a mass seen on plain chest x-ray films. Enhancement of a mass after contrast infusion is strong evidence for vascular origin. However, just as angiography may not accurately displaya clot-filled aneurysm, CT scans may also fail to show enhancement. With the recent development of two-dimensional cross-sectional echocardiography, visualization of the ascending-" and descending-" thoracic aorta has been
reported. Additional experience with this technique may add still another method by which to distinguish vascular from neoplastic chest densities. If these techniques fail to make a firm diagnosis of vascular origin, work-up for neoplasm should be pursued. Bronchoscopy with cytologic examination is performed. Neoplastic lesions frequently visualize on gallium-67 scan.i" and an abnormal scan would distinguish them from a vascular structure. An elevated level of carcinoembryonic antigen may also be seen with lung cancer. If abnormal, radionuclide scans of the liver, brain, and bone suggest that a lung density may be neoplastic. The presence of extrathoracic, paraneoplastic syndromes (inappropriate secretion of antidiuretic hormone, Cushing's syndrome, Eaton-Lambert syndrome, and others) favors the diagnosis of tumor. In the rare instance that neither neoplasm nor vascular lesion is proved, exploration of the chest may be necessary as a final diagnostic and therapeutic maneuver. Effective surgical therapy is now available for both intrathoracic neoplasms and vascular lesions, and failure to make a correct diagnosis is unacceptable. Furthermore, reassurance may be given to the patient with a benign vascular mass. REFERENCES Harris EJ: Aneurysms of the sinus of Valsalva. AJR 76:767 -772, 1956 2 Meschan I: Analysis of Roentgen Signs in General Radiology, Philadelphia, 1973, W. B. Saunders Company, pp 1117-1127 3 Crawford ES, Saleh SA, Schuessler JS: Treatment of an-
4
5 6
7
eurysm of transverse aortic arch. J THoRAc CARDIOVASC SURG 78:383-393, 1979 Wixson 0, Baltaxe HA, Sos TA: Pitfalls in the plain film evaluation of the thoracic aorta. The mimicry of aneurysms and adjacent masses and the value of aortography (Part I). Cardiovasc Radiol 2:69-76, 1979 Thomas TV: Looped innominate artery. J THoRAc CARDIOVASC SURG 54:719-722, 1967 Green RA: Enlargementof the innominateand subclavian arteries simulating mediastinal neoplasm. Am Rev Tuberc 79:790-798, 1959 Honig EI, Dubilier W, Steinberg I: Significance of the buckled innominate artery. Ann Intern Med 39:74-80, 1953
8 Thomas TV: Benign vascular shadows in chest x-rays. Geriatrics 26: 134-139, 1971 9 Thomas TV: Intrathoracic aneurysms of the innominate and subclavian arteries. J THoRAc CARDIOVASC SURG 63:461-47 I, 1972
10 Schumacher PO, Wright CB: Management of arteriosclerotic aneurysm of the innominate artery. Surgery 85:489-495, 1979
Volume 81
Vascular lesions simulating neoplasm
Number 2
263
February, 1981
II Gomes MMR, Bernatz PE, Forth RJ: Arteriosclerotic aneurysm of an aberrant right subclavian artery. Chest 54:549-552, 1968 12 Hunter JA, Dye WS, Javid H, Najafi H, Julian OC: Arteriosclerotic aneurysm of anomalous right subclavian artery. J THORAC CARDIOVASC SURG 59:754-758, 1970 13 Steinberg I, Engle MA, Holswade GR, Hagstrom JWC: Pseudocoarctation of the aorta associated with congenital heart disease. AJR 106:1-20, 1969 14 Higgins CB, Silverman NR, Harris RD, Albertson KW: Localized aneurysms of the descending thoracic aorta. Clin Radiol 26:475-482, 1975 15 Desai, MG: Widened and kinked descending part of the thoracic aorta simulating intra-thoracic tumor. Br J Radiol 30:391-392, 1957 16 Lyons HA, Calvy GL, Sammons BP: The diagnosis and classification of mediastinal masses. Ann Intern Med 51:897-932, 1959 17 Kelley MJ, Mannes EJ, Ravin CE: Mediastinal masses of va;cular origin. J THORAC CARDIOVASC SURG 76:559572, 1978 18 Abbott OA, Hopkins WA, Leigh TF: The role of angiocardiography and venography in mediastinal and paramediastinal lesions. J THORAC SURG 18:869-898, 1949 19 Kincaid OW, Brandenburg RO, Bernatz PE: Experiences with angiography as a guide to mediastinal exploration. JAMA 173:613-624, 1960 20 Neuhof H, Sussman ML, Nabatoff RA: Angiocardiography in the differential diagnosis of pulmonary neoplasm. Surgery 25:178-183, 1949 21 Steinberg I, Dotter CT: The differentiation of mediastinal
22
23 24
25
26
27
28
29
30
tumor and neoplasm. Value of angiocardiography. Br J Radiol 22:567-572, 1949 Steinberg I, Robb GP, Roche UJ: Differential diagnosis of mediastinal tumor and aortic aneurysm. NY State J Med 40:1168-1178,1940 Sussman ML: Differentiation of mediastinal tumor and aneurysm by angiocardiography. AJR 58:584-590, 1947 Sos TA, Sniderman KW, Wixson D: Pitfalls in the plain film evaluation of the thoracic aorta. The mimicry of aneurysms and adjacent masses and the value of aortography (Part II). Cardiovasc Radiol 2:77-83, 1979 Spray regen S, Jacobson HG: Angiographic differentiation of thoracic aneurysms and neoplasms. Vase Surg 10: 200-213, 1976 Sanders JH, Malave S, Neiman HL, Moran JM, Roberts AJ, Michaelis LL: Thoracic aortic imaging without angiography. Arch Surg 114:1326-1329, 1979 Livesay 11, Mink JH, Fee HJ, Bein ME, Sample WF, Mulder DG: The use of computed tomography to evaluate suspected mediastinal tumors. Ann Thorac Surg 27:305311, 1979 DeMaria AN, Bommer W, Neumann A, Weinert L, Bogren H, Mason DT: Identification and localization of aneurysms of the ascending aorta by cross-sectional echocardiography. Circulation 59:755-761, 1979 Mintz GS, Kotler MN, Segal BL, Parry WR: Twodimensional echocardiographic recognition of the descending thoracic aorta. Am J Cardiol 44:232-238, 1979 DeMeester TR, Bekerman C, Joseph JG, Toscano MS, Golomb H, Bitran J, Gross NJ, Skinner DB: Gallium-67 scanning for carcinoma of the lung. J THORAC CARDIOVASC SURG 72:699-708, 1976
Lesions of the thoracic aorta and its arch branches simulating neoplasm Abnormal radiographic densities in the midportion of the chest are most commonly caused by neoplasms, cysts, or inflammatory disease. However, vascular lesions may present an identical x-ray appearance, with no distinguishing clinical history or physical findings. The cardiothoracic surgeon must be aware of this similarity in order to ensure the most appropriate diagnostic and therapeutic approach. In our experience, the most frequent problem in differential diagnosis is a lesion of the thoracic aorta or its arch branches simulating neoplasm. Nine such cases are presented, with pertinent conventional radiographs, angiograms, and computed tomographic iC'T} scans. These are considered in anatomic sequence: (I) ruptured sinus of Valsalva aneurysm; (2) ascending aortic aneurysm; (3) tortuosity or aneurysm of the innominate and subclavian arteries; (4) transverse arch aneurysm; (5) pseudocoarctation; and (6) descending aortic aneurysm. Such vascular lesions must be considered early in the evaluation of any juxta-aortic chest density, particularly if the patient is hypertensive and has other manifestations of atherosclerosis. Angiography and computed tomography establish the diagnosis in most instances, although both are less reliable when thrombus fills all or part of an aneurysm. If these methods fail to establish a vascular orgin, the possibility of neoplasm is pursued. When neither a vascular nor neoplastic origin can be proved, surgical exploration is indicated in the otherwise good-risk patient.
David M. Shahian, M.D., Hushang Javid, M.D., Ph.D., L. Penfield Faber, M.D., C. Frederick Kittle, M.D., and Guy R. Matthew, M.D., Chicago, Ill.
Tortuosity and aneurysm of the thoracic aorta and its arch branches are common, particularly in elderly patients with hypertension and diffuse atherosclerosis. They appear radiographically as densities in the midportion of the chest and may be indistinguishable from cystic, inflammatory, or neoplastic disease. The history, clinical symptoms, and physical examination may also fail to differentiate between these entities. Inaccurate assessment by the thoracic surgeon may lead to exploration and discovery of an unsuspected vascular lesion for which no therapy is required or whose therapy requires different exposure or facilities than those available. Conversely, if a pulmonary neoplasm is misinterpreted as a benign vascular anomaly, the opportunity for early cure is lost. In an effort to emphasize this problem in differential
From the Departments of Cardiovascular-Thoracic Surgery and Radiology, Rush-Presbyterian-St. Luke'sMedical Center, 1753 West Congress Parkway, Chicago, Ill. Received for publication May 14, 1980. Accepted for publication June 9, 1980. Address for reprints: Hushang Javid, M.D., 1753 West Congress Parkway, Chicago, Ill. 60612.
diagnosis, we have selected the following cases from our own experience. These lesions of the thoracic aorta and its arch branches, all initially misinterpreted as neoplasms, are presented in anatomic sequence from the sinuses of Valsalva to the descending thoracic aorta (Fig. 1).
Case presentations Ruptured sinus of Valsalva aneurysm.
CASE 1. A 55-year-old man had a history of mild hypertension and presented to the emergency ward with atypical chest pain suggestive of a myocardial infarction. Physical examination revealed only a Grade 2/6 systolic ejection murmur along the sternal border. Chest roentgenogram demonstrated a large mass in the right anterior mediastinum (Fig. 2, A), thought to be neoplastic. After serial electrocardiograms and cardiac enzymes had ruled out an infarction, the patient was transferred to the thoracic surgery service. Exploration was performed through a right thoracotomy with a preoperative diagnosis of mediastinal neoplasm, probably thymoma or teratoma. There was a 9 by 9 cm mass arising from the right ventricle and the base of the ascending aorta. This mass was quite firm and was thought by some observers to be a cardiac tumor. However, the possibility of a ruptured sinus of Valsalva aneurysm was also considered, and further intervention was deferred. Postoperative angiography revealed a clot-filled sinus of Valsalva aneurysm with rupture into the right ventricle (Fig. 2, B).
0022-5223/81/020251 + 13$01.30/0 © 1981 The C. V. Mosby Co.
251
The Journal of
252 Shahian et al.
Thoracic and Cardiovascular Surgery
Aberrant R. Subclavian Aneurysm
Trans. Arch Aneurysm
Pseudocoarctation
Ruptured Sinus 01 Valsalva Aneurysm
Fig. 1. Lesions of the thoracic aorta and arch branches which may simulate neoplasm. Comment. Nonruptured sinus of Valsalva aneurysms are usually undetected unless angiography is performed for an associated cardiac defect. Those that have ruptured have a clinical spectrum ranging from asymptomatic to the classic presentation of acute chest or upper abdominal pain, heart failure, continuous murmur, and widened pulse pressure. Often the development of dyspnea, fatigue, and/or orthopnea is gradual. Chest pain may be only a transient phenomenon. The chest radiograph in unruptured aneurysm may be normal or may demonstrate a convexity at the base of the aorta, which forms a double contour along the right atrial border. Ruptured aneurysms may show cardiomegaly and increased pulmonary vascular markings. Our patient's presentation was quite unusual, with rupture into the right ventricle producing the radiographic and operative appearance of a neoplasm. Harris' described a similar case in which the aneurysmal wall contained calcium, further complicating the differential diagnosis. Ascending aortic aneurysm. CAS E 2. A 61-year-old woman had a past history of hypertension, adult onset diabetes, and tobacco abuse. She presented to her physician with cough, hemoptysis, and bilateral anterior chest pain. Posteroanterior and lateral chest x-ray roentgenograms (Fig. 3, A and B) revealed a mass in the upper left lung field, which on tomography was anterior and appeared separate from the aortic arch. Following a normal bronchoscopic study, the chest was explored through a left thoracotomy with a preoperative diagnosis of cancer. A large saccular aneurysm of the ascending aorta was discovered,
and the procedure was terminated. Postoperative aortography confirmed a clot-filled saccular aneurysm of the ascending aorta. The patient declined re-exploration and resection. Rupture of the aneurysm into the left side of the chest resulted in the patient's death 5 years later.
Comment. Aneurysms of the ascending aorta may result from atherosclerosis, syphilis, or Marfan's disease with annuloaortic ectasia. Except in the third instance, in which there is associated aortic insufficiency, early symptoms may be minimal or absent and the lesion may be discovered on a routine chest x-ray film. Erosion of the sternum or ribs and obstruction of the superior vena cava are late findings. In the typical fusiform ascending aneurysm, the classic radiographic finding is a mass projecting beyond the right heart border, such that a tangent drawn perpendicular to the margin falls lateral to the right atrial border. 2 The right heart border may be obscured on posteroanterior films, since both it and the aneurysm are anterior structures. Our patient's presentation was exceedingly unusual, with a large, saccular aneurysm of the ascending aorta projecting into the left side of the chest. The symptoms and plain radiographic appearance were indistinguishable from bronchogenic carcinoma. Transverse arch aneurysm.
CAS E 3. Three weeks prior to admission to our institution, a 79-year-old physician had been hospitalized elsewhere for treatment of a fractured hip. Routine chest roentgenogram revealed a 4 by 4 cm mass in the left suprahilar region (Fig. 4, A). The patient was normotensive and had a 20 pack-year smoking history. Other than chronic hoarseness, there were no signs of pulmonary or systemic illness. Tomography suggested bronchogenic carcinoma, although bronchoscopy revealed no endobronchial lesions. Computed tomographic (CT) scans revealed this mass to be between the inferior portion of the transverse arch and the superior portion of the pulmonary artery (Fig. 4, B). It could not be separated from these vascular structures, although on infusion it did not enhance. Because of these equivocal findings, aortography was performed. This study showed a saccular aneurysm of the inferior portion of the transverse arch, oriented toward the left (Fig. 4, C and D). In view of the patient's advanced age, absence of symptoms, and the small size of the aneurysm, surgical correction was deferred. CAS E 4. A 72-year-old woman presented with the recent onset of hoarseness and a 25 pound weight loss. She had a 30 pack-year smoking history, hypertension, and diabetes. Her son had died of oat cell carcinoma several years previously. Results of physical examination were normal, except for a left vocal cord paralysis. Chest x-ray film revealed a 2 by 3.5 em left hilar mass adjacent to the mid-transverse thoracic aorta (Fig. 5 A). Bronchoscopy and metastatic work-up showed no abnormalities. Aortography revealed severe atherosclerosis with irregularity of the infralateral portion of the transverse arch, thought to be diagnostic of a clot-filled aneurysm (Fig. 5, B and C). Exploration was declined by the patient. She died suddenly at home 4 months later.
Volume 81 Number 2
Vascular lesions simulating neoplasm
253
February, 1981
Fig. 2. A, Large mass of right anterior mediastinum in a 55-year-oldman with atypical chest pain. B, Angiography reveals a sinus of Valsalva aneurysm (arrow) with rupture into the right ventricle.
Fig. 3. Posteroanterior (A) and lateral (B) chest roentgenograms of an elderly womanwith a mass in the left upper
lung field. Exploration was performed, with a presumptive diagnosis of cancer. A large saccularaneurysmof the ascending aorta was found, with atypical presentation in the left side of the chest.
Comment. Aneurysms of the transverse arch are uncommon and may result from atherosclerosis, trauma, or dissection. Crawford, Saleh, and Schuessler recently have described their surgical experience with 30 such cases. These aneurysms may be fusiform or saccular, and most often they arise in the distal portion of the arch near the left subclavian artery. Because of their location near the narrow thoracic inlet and their close proximity to the trachea, esophagus, superior vena cava, and left recurrent laryngeal and phrenic nerves,
symptoms may be present even when the aneurysm is relatively small. These include cough, chest pain, airway obstruction, dysphagia, hemoptysis or hematernesis, and hoarseness. The aortic pulsation may be palpated through the chest wall in some instances. Characteristic radiographic findings include elongation of the aortic knob, right and posterior displacement of the trachea and esophagus, and downward displacement of the left bronchus. However, Wixson, Baltaxe, and SOS4 have recently reviewed the problems which
The Journal of
254 Shahian et al.
Thoracic and Cardiovascular Surgery
Fig. 4. A, A 79-year-old man with an asymptomatic left suprahilar mass (arrow). Tomography suggested bronchogenic carcinoma, but bronchoscopy showed no abnormality. B, Computed tomographic scan shows contiguity between the mass (arrow) and the transverse arch, but there was no enhancement with dye infusion. C and D. Arteriography revealed a saccular aneurysm of the inferior portion of the transverse arch (arrows).
can occur in making this diagnosis from radiographs. Often there is no calcification in the rim of the aneurysm, and the main body of the mass may appear separate from the aorta. Noncalcified aneurysms of the inferior arch may not be seen at all on plain x-ray films, their presence suggested only by obstructive sequelae. Finally, the aortic knob silhouette may be normal if a
transverse arch aneurysm arises anteriorly, and the true nature of the lesion may not be appreciated. A high index of suspicion for any lesion near the aortic knob is the first step in accurate diagnosis. Angiography usually demonstrates the aneurysm, although the presence of clot may result in underestimation of its size. Occasionally only the neck of the aneurysm may
Volume 81 Number 2
Vascular lesions simulating neoplasm
255
February, 1981
be demonstrated, seen as an irregular border of the transverse arch. CT scans may better show the size and configuration of the aneurysm. However, if clot-filled, the aneurysm may not enhance with infusion, and the differentiation from neoplasm may still be uncertain. Innominate-subclavian artery tortuosity and aneurysm. 5. A 61-year-old woman was a one pack per day smoker with a history of hypertension, chronic renal failure, and scoliosis; she had no pulmonary symptoms. She was admitted for evaluation of peripheral neuropathy and was found on roentgenography to have a mass at the right lung apex (Fig. 6, A). Comparison with old films demonstrated enlargement of this area during the previous year, and pulmonary neoplasm was considered the most likely diagnosis. However, because a prominent right supraclavicular subclavian pulsation was noted, vascular origin of the mass was also considered. Aortography was performed as the final preoperative study. This demonstrated a tortuous, kinked right subclavian artery which, in combination with the patient's scoliosis, resulted in the abnormal right apical density (Fig. 6, B). CASE 6. A 73-year-old woman was a nonsmoker, in good health except for chronic hypertension. She was referred because of an asymptomatic 2 by 7 ern mass in the right superior mediastinum (Fig. 7, A). Because of its characteristic location and smooth convex border, a vascular lesion was also considered. Tomography revealed an anterior mass arising at the level of the aortic arch (Fig. 7, B) and a contiguous mass posteriorly (Fig. 7, C). Angiography confirmed tortuous, aneurysmal innominate and subclavian arteries (Fig. 7, D). CT scan demonstrated the anterior vascular lesion and the adjacent posterior mass, which did not enhance with infusion (Fig. 7, E). Although a coexisting pulmonary mass could not be excluded, it was felt that this represented a posterior, clot-filled extension of the innominate aneurysm. The patient declined any further diagnostic or therapeutic intervention. CAS E 7. A 68-year-old man presented to an outside hospital with dysphagia and a density in the right posterosuperior part of the chest on roentgenography (Fig. 8, A and B). He underwent right thoracotomy with a preoperative diagnosis of neoplasm, and an aneurysm of the right subclavian artery was found. It was impossible to obtain control of this vessel, however, and the procedure was terminated. Following transfer to our institution, arteriography demonstrated an aneurysm of an aberrant right subclavian artery (Fig. 8, C and D). Surgical correction was undertaken through a left thoracotomy. CASE
Comment. The innominate artery is fixed between its origin at the aorta and its bifurcation into the carotid and subclavian arteries. Normally, the entire artery and its bifurcation lie well within the right superior mediastinal shadow, formed by the innominate vein and the superior vena cava. With age, chronic hypertension, and generalized atherosclerosis, the innominate artery may undergo elongation, tortuosity, and/or kinking. 5 This appears radiographically as an anterior, convex density arising at the level of the aortic arch. 6 A useful roentgenographic sign is the absence of a distinct bor-
Fig. SA. Roentgenogram of a 72-year-old woman with hypertension and a 30 pack-year smoking history. Her son had died of oat cell cancer several years earlier, and she presented with hoarseness and a 25 pound weight loss. The chest x-ray film reveals a 2 by 3.5 em left hilar mass (arrow) adjacent to the mid- transverse thoracic aorta.
der superiorly. This results from the loss of lung-vessel interface as the artery ascends toward the thoracic outlet. Calcium may be present in the wall. This is not an uncommon lesion, with a significant incidence reported by Honig, Dubilier, and Steinberg? in an angiographic study of hypertensive patients with atherosclerosis. Such a density has been misinterpreted as a mediastinal or right upper lobe lesion. These are most commonly asymptomatic, discovered on routine chest x-ray films in elderly hypertensive patients. 8 Tracheoesophageal symptoms or venous compression infrequently occur. Cerebral vascular symptoms secondary to looped innominate artery are rare, as is Homer's syndrome. Occasionally, a prominent supraclavicular pulsation or bruit may be present. As emphasized by Thomas," the lesion itself is benign and has an excellent prognosis without therapy. It is most important to avoid hazardous and unnecessary invasive techniques such as mediastinoscopy or large cutting needle biopsy. Angiography and CT scanning are usually diagnostic. The diagnosis must be established with absolute certainty before a decision is made to observe such a lesion, so as not to ignore an actual neoplasm and thus lose the opportunity for effective therapy. True atherosclerotic aneurysms of the innominate artery are uncommon compared to tortuosity and buckling." Schumacher and Wright,IO reviewing the English
The Journal of
256 Shahian et al.
Thoracic and Cardiovascular Surgery
Fig. S. Coot'd. Following a negative evaluation for neoplasm, anteroposterior (B) and lateral (C) arteriograms were performed. These demonstrated severe atherosclerosis of the inferolateral transverse arch with irregularity of the border and several small aneurysms (arrows). This was thought to represent the neck of a larger, thrombus-filled aneurysm.
Fig. 6. A. Roentgenogram of a 61-year-old woman with peripheral neuropathy and a mass (arrow) at the right lung apex. B. Aortography reveals a tortuous, kinked right subclavian artery (arrow). Its radiographic appearance is accentuated by the patient's mild scoliosis.
Volume 81 Number 2
Vascular lesions simulating neoplasm
February, 1981
Fig. 7. A, Roentgenogram of a 73-year-old hypertensive woman with an asymptomatic right superior mediastinal mass. B. Tomography reveals a convex anterior mass arising at the level of the aortic arch. The fact that the superior margin is less distinct suggests its vascular origin (see text). C. Additional tomographic sections demonstrate a second, posterior mass. D. Angiography confirms the presence of innominate-subclavian tortuosity and aneurysm.
257
258
The Journal of Thoracic and Cardiovascular
Shahian et al.
Surgery
Fig. 7E. Computed tomographic scan demonstrates both the aneurysm anteriorly and the posterior density seen on regular tomography. Although a coexisting neoplasm could not be excluded, it was felt that this represented a clot-filled nonopacifying portion of the aneurysm. language literature, collected 47 case reports of patients who had undergone operation for a nontraumatic innominate aneurysm. Most such patients present with an asymptomatic right superior mediastinal mass. However, because such aneurysms represent a larger mass within the relative confinement of the superior mediastinum, the range of symptoms is broader than that seen with simple tortuosity. These may include dysphagia, hoarseness, Horner's syndrome, supraclavicular pain, brachial plexus dysfunction with pain or weakness, and upper extremity edema. Cerebral vascular symptoms may result from embolized debris or from associated stenosis. Physical findings, if present, include prominent suprasternal or supraclavicular pulsation and evidence of central venous compression. Angiography and CT scans are the most valuable diagnostic techniques. Aberrant right subclavian artery is the most common congenital anomaly of the aortic arch. II The origin of the artery is at or just distal to the left subclavian, and it most commonly courses in a superior and rightward direction behind the esophagus. Aneurysms of the innominate and subclavian arteries are rare, and aneurysms of an aberrant right subclavian artery are exceedingly uncommon. Hunter and associates'> have described their experience with three such patients, only two cases having been previously reported in the literature. The most common presentation is an asymptomatic right superior mediastinal mass. Dysphagia may occur with increasing size of the aneurysm. Such lesions have been mistaken for neoplasm and for innominate aneurysm. However, a barium esophagogram
reveals the characteristic anterior displacement of the dorsal aspect of the esophagus, at or just above the level of the arch and extending cephalad and to the right. An aortogram with frontal, lateral, and oblique projections confirms the diagnosis. Accurate preoperative diagnosis is particularly important in this lesion. The radiographic appearance may lead to an innappropriate surgical approach through a right thoracotomy, which would make proximal control of the aneurysm impossible and necessitate a second procedure. Pseudocoarctation. 8. A 34-year-old asymptomatic man was referred becauseof an abnormal chest x-ray film. Routine radiographs were interpreted as showing a mass in the anterior mediastinumjust above the aortic knob (Fig. 9,A). This was felt to be a mediastinal neoplasm or cyst. Vascularorigin of the lesion was thought unlikely, and angiography was not performed. Exploration was carried out through an axillary thoracotomy, and the only finding was a pseudocoarctation of the aorta. Distal perfusion pressure and pulses were excellent, and no therapy was indicated. Postoperative angiography confirmed the pseudocoarctation (Fig. 9, B). CASE
Comment. Pseudocoarctation is an acute kinking or anterior "buckling" (Fig. 9, C) of the thoracic aorta at the level of the ligamentum. The aorta proximal to the kink is elongated and arises higher in the mediastinum than usual. This results from the failure of normal contraction of some arterial segments during embryogenesis.!" This condition is to be distinguished from acquired aortic tortuosity, which occurs in elderly, hypertensive patients with atherosclerosis. Isolated pseudocoarctation produces no symptoms
Volume 81 Number 2
Vascular lesions simulating neoplasm
259
February, 1981
Fig. 8. A, Posteroanterior chest film of a 68-year-old man with dysphagia and a density in the right superior mediastinum (arrow). B, Lateral film demonstrates a mass posterior to the esophagus. Aortography in the anteroposterior (C) and right posterior oblique projections (D) reveals a partially thrombosed aneurysm of an aberrant right subclavian artery. Both common carotid arteries originate from a common trunk. and only rarely is a flow murmur heard. Radiographically, it resembles a left para-aortic mediastinal tumor or lymphoma. However, the apparent aortic knob and adjacent mass are actually both parts of a "buckled" aorta, seen in an atypical relationship to each other. The inferior convexity is usually interpreted
as an aortic knob and the superior one as a mass. However, as demonstrated in Fig. 9, B, the superior density is in reality the knob, the junction between the transverse arch and descending aorta near the origin of the subclavian artery. For this developmental anomaly to be distinguished
The Journal of Thoracic and Cardiovascular Surgery
260 Shahian et ai.
Fig. 9. A. Roentgenogram of an asymptomatic 34-year-old man with a mediastinal mass (arrow) just superior to the aortic knob, thought to be cyst or neoplasm. B. Anteroposterior aortogram demonstrates typical pseudocoarctation. Distal pulses were normal, and there was no rib-notching. absolutely from true coarctation, there must be no pressure differential across it and no collateral vessels. No surgical intervention is required. It must be differentiated from other masses in the left superior mediastinum-true aneurysms, mediastinal cysts, or neoplasms. Arteriography is the method of choice, although CT scans and two-dimensional echocardiography may supplant this more invasive technique. Descending thoracic aneurysm. 9. A 63-year-old white woman with chronic hypertension presented to another institution with a history of pain in the right side of the chest. A chest x-ray film revealed a mass in the right inferoposterior mediastinum (Fig. 10, A). Results of bronchoscopy, mediastinoscopy, and an upper gastrointestinal tract series were normal. The chest was explored through a right thoracotomy, with a preoperative diagnosis of mediastinal neurogenic tumor. An aneurysm of the descending thoracic aorta was found, which could not be resected through this approach. The procedure was terminated, and the woman was referred to the cardiovascular service. Angiography demonstrated that the aneurysm extended just caudad to the diaphragm (Fig. 10, B), and resection and graft replacement were accomplished through a left thoracoabdominal incision. CA S E
Fig. 9C. Lateral aortogram of a similar patient with pseudocoarctation demonstrates acute anterior buckling.
Comment. Nondissecting aneurysms of the descending aorta are most commonly atherosclerotic, the remainder being traumatic or mycotic. These may be fusiform dilatations in a diffusely ectatic aorta or may be localized;':' Most are discovered in asymptomatic patients on routine chest x-ray films. In advanced cases, clinical presentations include back pain, evi-
Volume 81 Number 2
Vascular lesions simulating neoplasm
261
February, 1981
Fig. 10. A. Roentgenogram of a 63-year-old hypertensive woman with chest pain and a mass in the right inferoposterior mediastinum. B, Thoracotomy was performed, and a large descending thoracic aneurysm was discovered. Postoperative angiography shows extension of the aneurysm just caudad to the diaphragm. Marked tortuosity accounts for the atypical presentation in the right side of the chest. dence of vertebral erosion or spinal cord destruction, airway obstruction and atelectasis, or hemoptysis. In their more diffuse form, descending aneurysms project lateral to the left heart border. Esophageal displacement is common, since this structure is contiguous throughout the course of the descending aorta. Localized aneurysms of the descending aorta may appear as a right or left hilar or retrocardiac mass .14 With tortuosity of the descending aorta, the aneurysm may be projected into the right cardiophrenic angle on frontal radiographs and into the posterior mediastinum on lateral views. It may thus appear to be a pulmonary or mediastinal neoplasm. 15
Discussion Abnormal radiographic densities in the midportion of the chest are most commonly found to be inflammatory, cystic, or neoplastic. However, in a study of 782 mediastinal masses, Lyons, Calvy, and Sammons!" found 9% of such lesions to be vascular in origin. Kelley, Mannes, and Ravin'? have divided such vascular densities into four groups: (1) systemic venous system,
(2) pulmonary venous system, (3) pulmonary arterial system, (4) systemic arteries. Many such lesions are congenital or acquired anomalies requiring no specific therapy (azygos or hemiazygos vein enlargement, pulmonary venous varix, persistent left superior vena cava, idiopathic dilatation of the pulmonary trunk). Other more significant congenital cardiovascular lesions include anomalous pulmonary venous return, anomalous left pulmonary artery, and aortic or pulmonary stenosis. These have associated physical findings and clinical course which expedite their correct diagnosis and therapy. In our experience, abnormalities of the thoracic aorta and its arch branches present the most common such problem in differential diagnosis. With the exception of pseudocoarctation, these lesions are distinguished by their initial discovery in older patients with hypertension and atherosclerosis; they are often difficult to distinguish from neoplasms. Use of an inappropriate diagnostic technique such as cutting needle biopsy or mediastinoscopy may be fatal in such patients, and failure to establish the correct diagnosis may prevent or
262
The Journal of Thoracic and Cardiovascular Surgery
Shahian et al.
delay the treatment of either a vascular or neoplastic lesion. A lesion of the thoracic aorta or major arch branch should be considered early in the evaluation of any juxta-aortic mass. Plain radiographic features are variable and rarely diagnostic. Likewise, the clinical symptoms of patients with neoplastic and vascular lesions may overlap significantly. Presentations range from totally asymptomatic to vocal cord paralysis, cough, hemoptysis, chest pain, bronchial compression with atelectasis or stridor, or dysphagia. Physical findings suggestive of a vascular origin include severe chronic hypertension, a pulsating mass at the base of the neck, a prominent aortic pulsation in the anterior chest, or a bruit from a kinked vessel. Prior to the late 1940s many central chest densities were merely observed or were irradiated empirically, because they were considered to be unresectable neoplasms. With the advent of angiography and cardiovascular surgery, great interest developed in defining those masses which were vascular in origin. Most older methods of distinguishing vascular from nonvascular lesions-e.g., calcification or the presence of pulsation at fluoroscopy-fell into disrepute. Numerous investigators reported the diagnostic superiority of angiography.1R-23 With increasing experience, it has become apparent that even this method is not infallible. A thrombus-filled aneurysm might not visualize at all or might be only suggested by an irregular aortic border. Wixson," SOS,24 and their associates have recently emphasized this diagnostic problem, and Sprayregen and Jacobson" have enumerated several useful signs in interpreting thoracic aortograms. On the basis of their experience, the more subtle radiographic findings of thoracic aneurysms include slight widening of the aortic lumen, aortic wall thickening, small ulcerlike collections of contrast (border irregularity and spiculation), and local nonopacification of intercostal arteries. They also call attention to the frequent association with abdominal aneurysms. CT scanning, especially with dye enhancement, is a useful new tool with which to image the thoracic aorta'" and other mediastinal masses.F It can at least characterize the extent and localization of a mass seen on plain chest x-ray films. Enhancement of a mass after contrast infusion is strong evidence for vascular origin. However, just as angiography may not accurately displaya clot-filled aneurysm, CT scans may also fail to show enhancement. With the recent development of two-dimensional cross-sectional echocardiography, visualization of the ascending-" and descending-" thoracic aorta has been
reported. Additional experience with this technique may add still another method by which to distinguish vascular from neoplastic chest densities. If these techniques fail to make a firm diagnosis of vascular origin, work-up for neoplasm should be pursued. Bronchoscopy with cytologic examination is performed. Neoplastic lesions frequently visualize on gallium-67 scan.i" and an abnormal scan would distinguish them from a vascular structure. An elevated level of carcinoembryonic antigen may also be seen with lung cancer. If abnormal, radionuclide scans of the liver, brain, and bone suggest that a lung density may be neoplastic. The presence of extrathoracic, paraneoplastic syndromes (inappropriate secretion of antidiuretic hormone, Cushing's syndrome, Eaton-Lambert syndrome, and others) favors the diagnosis of tumor. In the rare instance that neither neoplasm nor vascular lesion is proved, exploration of the chest may be necessary as a final diagnostic and therapeutic maneuver. Effective surgical therapy is now available for both intrathoracic neoplasms and vascular lesions, and failure to make a correct diagnosis is unacceptable. Furthermore, reassurance may be given to the patient with a benign vascular mass. REFERENCES Harris EJ: Aneurysms of the sinus of Valsalva. AJR 76:767 -772, 1956 2 Meschan I: Analysis of Roentgen Signs in General Radiology, Philadelphia, 1973, W. B. Saunders Company, pp 1117-1127 3 Crawford ES, Saleh SA, Schuessler JS: Treatment of an-
4
5 6
7
eurysm of transverse aortic arch. J THoRAc CARDIOVASC SURG 78:383-393, 1979 Wixson 0, Baltaxe HA, Sos TA: Pitfalls in the plain film evaluation of the thoracic aorta. The mimicry of aneurysms and adjacent masses and the value of aortography (Part I). Cardiovasc Radiol 2:69-76, 1979 Thomas TV: Looped innominate artery. J THoRAc CARDIOVASC SURG 54:719-722, 1967 Green RA: Enlargementof the innominateand subclavian arteries simulating mediastinal neoplasm. Am Rev Tuberc 79:790-798, 1959 Honig EI, Dubilier W, Steinberg I: Significance of the buckled innominate artery. Ann Intern Med 39:74-80, 1953
8 Thomas TV: Benign vascular shadows in chest x-rays. Geriatrics 26: 134-139, 1971 9 Thomas TV: Intrathoracic aneurysms of the innominate and subclavian arteries. J THoRAc CARDIOVASC SURG 63:461-47 I, 1972
10 Schumacher PO, Wright CB: Management of arteriosclerotic aneurysm of the innominate artery. Surgery 85:489-495, 1979
Volume 81
Vascular lesions simulating neoplasm
Number 2
263
February, 1981
II Gomes MMR, Bernatz PE, Forth RJ: Arteriosclerotic aneurysm of an aberrant right subclavian artery. Chest 54:549-552, 1968 12 Hunter JA, Dye WS, Javid H, Najafi H, Julian OC: Arteriosclerotic aneurysm of anomalous right subclavian artery. J THORAC CARDIOVASC SURG 59:754-758, 1970 13 Steinberg I, Engle MA, Holswade GR, Hagstrom JWC: Pseudocoarctation of the aorta associated with congenital heart disease. AJR 106:1-20, 1969 14 Higgins CB, Silverman NR, Harris RD, Albertson KW: Localized aneurysms of the descending thoracic aorta. Clin Radiol 26:475-482, 1975 15 Desai, MG: Widened and kinked descending part of the thoracic aorta simulating intra-thoracic tumor. Br J Radiol 30:391-392, 1957 16 Lyons HA, Calvy GL, Sammons BP: The diagnosis and classification of mediastinal masses. Ann Intern Med 51:897-932, 1959 17 Kelley MJ, Mannes EJ, Ravin CE: Mediastinal masses of va;cular origin. J THORAC CARDIOVASC SURG 76:559572, 1978 18 Abbott OA, Hopkins WA, Leigh TF: The role of angiocardiography and venography in mediastinal and paramediastinal lesions. J THORAC SURG 18:869-898, 1949 19 Kincaid OW, Brandenburg RO, Bernatz PE: Experiences with angiography as a guide to mediastinal exploration. JAMA 173:613-624, 1960 20 Neuhof H, Sussman ML, Nabatoff RA: Angiocardiography in the differential diagnosis of pulmonary neoplasm. Surgery 25:178-183, 1949 21 Steinberg I, Dotter CT: The differentiation of mediastinal
22
23 24
25
26
27
28
29
30
tumor and neoplasm. Value of angiocardiography. Br J Radiol 22:567-572, 1949 Steinberg I, Robb GP, Roche UJ: Differential diagnosis of mediastinal tumor and aortic aneurysm. NY State J Med 40:1168-1178,1940 Sussman ML: Differentiation of mediastinal tumor and aneurysm by angiocardiography. AJR 58:584-590, 1947 Sos TA, Sniderman KW, Wixson D: Pitfalls in the plain film evaluation of the thoracic aorta. The mimicry of aneurysms and adjacent masses and the value of aortography (Part II). Cardiovasc Radiol 2:77-83, 1979 Spray regen S, Jacobson HG: Angiographic differentiation of thoracic aneurysms and neoplasms. Vase Surg 10: 200-213, 1976 Sanders JH, Malave S, Neiman HL, Moran JM, Roberts AJ, Michaelis LL: Thoracic aortic imaging without angiography. Arch Surg 114:1326-1329, 1979 Livesay 11, Mink JH, Fee HJ, Bein ME, Sample WF, Mulder DG: The use of computed tomography to evaluate suspected mediastinal tumors. Ann Thorac Surg 27:305311, 1979 DeMaria AN, Bommer W, Neumann A, Weinert L, Bogren H, Mason DT: Identification and localization of aneurysms of the ascending aorta by cross-sectional echocardiography. Circulation 59:755-761, 1979 Mintz GS, Kotler MN, Segal BL, Parry WR: Twodimensional echocardiographic recognition of the descending thoracic aorta. Am J Cardiol 44:232-238, 1979 DeMeester TR, Bekerman C, Joseph JG, Toscano MS, Golomb H, Bitran J, Gross NJ, Skinner DB: Gallium-67 scanning for carcinoma of the lung. J THORAC CARDIOVASC SURG 72:699-708, 1976