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Paratracheal air cyst: Case report of a tracheal diverticulum
European Journal of Radiology Extra 64 (2007) 91–93
Paratracheal air cyst: Case report of a tracheal diverticulum Patrick S. Scherr, Elisabeth Garzoli, Thomas Frauenfelder ∗ Institute of Diagnostic Radiology, Department Radiology, University Hospital of Zurich, R¨amistrasse 100, 8091 Zurich, Switzerland Received 18 June 2007; received in revised form 17 September 2007; accepted 18 September 2007
Abstract We present the case of a 56-year-old man with clinical symptoms of a myocardial infarction in whom we accidentally found a right dorsolateral paratracheal air cyst on CT scan at admission. The final diagnosis of a tracheal diverticulum was made after having excluded the other differential diagnoses of a paratracheal air cyst. Helpful for the diagnosis was a follow-up CT scan performed both in expiration and during valsalva manoeuvre that allowed to show the origin of the communicating duct in the tracheal wall and the changes in extent of the tracheal diverticulum. Additional findings were signs of chronic bronchitis and a panlobular lung emphysema, both characteristic companions of tracheal diverticulum. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Computed tomography; Trachea; Diverticulum
1. Case report A 56-year-old man was brought to our emergency room after having collapsed on an early morning walk. Before collapsing he felt epigastric and retrosternal burning pain, malaise, nausea and sweating. After having regained consciousness he had left thoracic pain, radiating into the left arm, neck and abdomen. The patient never smoked and did not take any oral medication. He reported a single episode of vomiting on the same morning and hoarseness, sore throat and dry cough for some days as well as a 1 week history of dysphagia and odynophagia for solid food and liquids. ECG and laboratory signs were negative for myocardial infarction and a CT scan excluded pulmonary embolism. The sole findings were a right dorsolateral paratracheal cystic lesion filled with air and a slight panlobular emphysema. The cystic lesion was multilobulated and septated. The maximal axial and craniocaudal diameters were 33 and 54 mm, respectively. The lesion had close anatomic relations to the trachea at the level C6 to T1 (Fig. 1), suggesting a connection to the trachea. There was no fluid within the thin walled ∗
Corresponding author. Tel.: +41 44 255 9383; fax: +41 44 255 4443. E-mail address: [email protected] (T. Frauenfelder).
1571-4675/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2007.09.003
cyst and no sign of surrounding inflammation. The lesion was clearly separated from the lung and esophagus by fatty tissue. Based on these findings our first diagnosis was an accidental finding of a tracheal diverticulum, a differential diagnosis for paratracheal air cysts. Other differentials are laryngocele, pharyngocele, Zenkers diverticulum, apical hernia of the lung and apical paraseptal blebs or bullae [1]. The latter two were ruled out by the CT scan, the laryngocele was excluded by a laryngoscopy. The esophagogastro-duodenoscopy and a barium swallow study showed no pathologic findings, especially a Zenker’s diverticulum was ruled out. A subsequent bronchoscopy could not reveal a connecting duct between the trachea and the cystic lesion, but showed findings of a chronic bronchitis. As these examinations did not confirm the tracheal diverticulum, a spontaneous remission of the cystic lesion was suggested and an additional CT scan was applied. To prove the tracheal diverticulum we have performed this second scan in expiration and during valsalva manoeuvre. This study confirmed the cystic lesion with change in extent of the tracheal diverticulum on corresponding sagittal images (Fig. 2) and a small connection to the trachea seen on corresponding axial images (Fig. 3). During the hospitalisation the odynophagia improved spontaneously and gradual return to solid food could be established.
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P.S. Scherr et al. / European Journal of Radiology Extra 64 (2007) 91–93
2. Discussion
Fig. 1. Volume rendering image showing air inside the tracheal diverticulum (arrow) and the esophagus (arrowhead). Both are clearly separated from each other. There is no connection between the tracheal diverticulum and the lung.
This case report describes the typical radiological findings of a tracheal diverticulum. The tracheal diverticulum is a rarely described lesion, although Goo et al. [1] have found them in their prospective study in 2% of patients undergoing chest CT (73 out of 3645 patients). In an autopsy series by MacKinnon [2], tracheal diverticula are reported in 1% (eight cases in 867 necropsies) of patients. Apart of these studies, only a few cases of paratracheal air cysts have been published (e.g. [3,4]). When reviewing the literature, we found different terms for this pathologic entity, as tracheocele, tracheal diverticulum and tracheogenic cyst [5]. Tracheal diverticula can be separated in a congenital and an acquired form, the former being thick walled with cartilaginous rings and smooth muscle, the latter being larger, thin walled and appearing at any level of the trachea. Goo et al. [1] have examined 65 patients with CT evidence of a paratracheal air cyst, lacking histologic or pathologic correlation. The vast majority of these cysts were located on the right paratracheal region at the T2 level. The predilection for the right side is supposed to be due to the lacking support of the left lying esophagus [2]. The point of least resistance seems to be at the level of T2 at the thoracic inlet because it is the transitional point between the extrathoracic and intrathoracic trachea [1]. According to MacKinnon [2], the diverticulum arises by cystic distention of the ducts of mucous glands, finally resulting in a simple epitheliumlined fibrous-walled cyst. The largest vertical diameter in the studies of Goo et al. [1] and MacKinnon [2] were 25 and 30 mm, respectively. Both have observed a positive correlation between chronic cough or lung emphysema and tracheal diverticulum [1,2]. A thread-like communication between the air cyst and trachea was found in only five patients (8%) that underwent
Fig. 2. Sagittal multiplanar reformation through the trachea and the tracheal diverticulum depicting the differences of the extent of the air filled cyst lying in front of the vertebra between expiration (a) and valsalva manoeuvre (b).
P.S. Scherr et al. / European Journal of Radiology Extra 64 (2007) 91–93
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Fig. 3. (A) Tracheal diverticulum in expiration. The connecting duct (arrow) is only slightly visible. (B) Dilatation of the connecting duct (arrow) during valsalva manoeuvre. On both images the esophagus is clearly separated from the lesion.
thick-section CT, and in three (of five) patients that underwent helical CT scanning in thin section (less than 4 mm) [1]. On respiratory dynamic CT, the paratracheal cysts expanded during forced expiration and shrank during inspiration, suggesting a communication between the cyst and the trachea and thus probably representing tracheal diverticulum. This communication could not be seen by means of bronchoscopy (n = 19) or bronchography (n = 4) [1]. “Paratracheal air cyst” is a non-specific term for a broad differential diagnosis of a paratracheal air collection. Besides tracheal diverticulum, this differential diagnosis also includes laryngocele, pharyngocele, Zenker’s diverticulum, apical hernia of the lung and apical paraseptal blebs or bullae [1]. According to Goo et al. [1] cough, sputum, hemoptysis, dyspnea and chest pain are the most common clinical findings. The clinical presentation of our patient with chest pain, dysphagia and odynophagia is very atypical for a tracheal diverticulum, leaving the impression that clinical findings and diverticulum were unrelated one to another. In the literature we found only one reported case presenting with dysphagia [5]. Although we did not prove the diagnosis by histology, the findings on CT scan and additional examinations could narrow the differential diagnosis down to only tracheal diverticulum as cause for the paratracheal air cyst, although the clinical symptoms with collapse, chest pain, dysphagia and odynophagia are not very common for a tracheal diverticulum. The persistence of a paratracheal air cyst in the follow-up CT scan performed in expiration and under valsalva manoeuvre 6 days after the initial scan strengthened our first diagnosis of a tracheal diverticulum. In addition we now could visual-
ize a change in extent between the expiration and valsalva manoeuvre (Fig. 2) and an air bubble in the tracheal wall (Fig. 3), most probably being the origin of the communicating duct. 3. Conclusion A tracheal diverticulum is a rare finding. It is an important differential diagnosis for paratracheal air cysts. The diagnosis is mostly done by ruling out the other differential diagnoses, like laryngocele, pharyngocele, Zenker’s diverticulum, apical hernia of the lung and apical paraseptal blebs or bullae. In many cases a direct communication between a right dorsolateral paratracheal air cyst and the trachea at the thoracic inlet cannot be visualized on standard chest-CT. A follow-up CT scan performed in valsalva manoeuvre – or forced expiration as in another study [1] – is helpful and may inflate the communicating channel to the trachea and may shows changes in extent of the tracheal diverticulum. References [1] Goo JM, Im J, Ahn JM, et al. Right paratracheal air cysts in the thoracic inlet: clinical and radiologic significance. AJR 1999;173:65–70. [2] MacKinnon D. Tracheal diverticula. J Pathol Bacteriol 1953;65:513–7. [3] Soto-Hurtado EJ, Pe˜nuela-Ru´ız L, Rivera-S´anchez I, et al. Tracheal diverticulum: a review of the literature. Lung 2006;184:303–7. [4] Tanaka H, Mori Y, Kurokawa K, et al. Paratracheal air cysts communicating with the trachea: CT findings. J Thor Imag 1997;12:38–40. [5] Djamouri F, Le Pimpec Barthes F, Pheulpin G, et al. Kystes a´eriens” d’origine trach´eale: probl`emes nosologiques et fr´equence r´eelle. Rev Mal Respir 2002;19:523–6.
Paratracheal air cyst: Case report of a tracheal diverticulum Patrick S. Scherr, Elisabeth Garzoli, Thomas Frauenfelder ∗ Institute of Diagnostic Radiology, Department Radiology, University Hospital of Zurich, R¨amistrasse 100, 8091 Zurich, Switzerland Received 18 June 2007; received in revised form 17 September 2007; accepted 18 September 2007
Abstract We present the case of a 56-year-old man with clinical symptoms of a myocardial infarction in whom we accidentally found a right dorsolateral paratracheal air cyst on CT scan at admission. The final diagnosis of a tracheal diverticulum was made after having excluded the other differential diagnoses of a paratracheal air cyst. Helpful for the diagnosis was a follow-up CT scan performed both in expiration and during valsalva manoeuvre that allowed to show the origin of the communicating duct in the tracheal wall and the changes in extent of the tracheal diverticulum. Additional findings were signs of chronic bronchitis and a panlobular lung emphysema, both characteristic companions of tracheal diverticulum. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Computed tomography; Trachea; Diverticulum
1. Case report A 56-year-old man was brought to our emergency room after having collapsed on an early morning walk. Before collapsing he felt epigastric and retrosternal burning pain, malaise, nausea and sweating. After having regained consciousness he had left thoracic pain, radiating into the left arm, neck and abdomen. The patient never smoked and did not take any oral medication. He reported a single episode of vomiting on the same morning and hoarseness, sore throat and dry cough for some days as well as a 1 week history of dysphagia and odynophagia for solid food and liquids. ECG and laboratory signs were negative for myocardial infarction and a CT scan excluded pulmonary embolism. The sole findings were a right dorsolateral paratracheal cystic lesion filled with air and a slight panlobular emphysema. The cystic lesion was multilobulated and septated. The maximal axial and craniocaudal diameters were 33 and 54 mm, respectively. The lesion had close anatomic relations to the trachea at the level C6 to T1 (Fig. 1), suggesting a connection to the trachea. There was no fluid within the thin walled ∗
Corresponding author. Tel.: +41 44 255 9383; fax: +41 44 255 4443. E-mail address: [email protected] (T. Frauenfelder).
1571-4675/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2007.09.003
cyst and no sign of surrounding inflammation. The lesion was clearly separated from the lung and esophagus by fatty tissue. Based on these findings our first diagnosis was an accidental finding of a tracheal diverticulum, a differential diagnosis for paratracheal air cysts. Other differentials are laryngocele, pharyngocele, Zenkers diverticulum, apical hernia of the lung and apical paraseptal blebs or bullae [1]. The latter two were ruled out by the CT scan, the laryngocele was excluded by a laryngoscopy. The esophagogastro-duodenoscopy and a barium swallow study showed no pathologic findings, especially a Zenker’s diverticulum was ruled out. A subsequent bronchoscopy could not reveal a connecting duct between the trachea and the cystic lesion, but showed findings of a chronic bronchitis. As these examinations did not confirm the tracheal diverticulum, a spontaneous remission of the cystic lesion was suggested and an additional CT scan was applied. To prove the tracheal diverticulum we have performed this second scan in expiration and during valsalva manoeuvre. This study confirmed the cystic lesion with change in extent of the tracheal diverticulum on corresponding sagittal images (Fig. 2) and a small connection to the trachea seen on corresponding axial images (Fig. 3). During the hospitalisation the odynophagia improved spontaneously and gradual return to solid food could be established.
92
P.S. Scherr et al. / European Journal of Radiology Extra 64 (2007) 91–93
2. Discussion
Fig. 1. Volume rendering image showing air inside the tracheal diverticulum (arrow) and the esophagus (arrowhead). Both are clearly separated from each other. There is no connection between the tracheal diverticulum and the lung.
This case report describes the typical radiological findings of a tracheal diverticulum. The tracheal diverticulum is a rarely described lesion, although Goo et al. [1] have found them in their prospective study in 2% of patients undergoing chest CT (73 out of 3645 patients). In an autopsy series by MacKinnon [2], tracheal diverticula are reported in 1% (eight cases in 867 necropsies) of patients. Apart of these studies, only a few cases of paratracheal air cysts have been published (e.g. [3,4]). When reviewing the literature, we found different terms for this pathologic entity, as tracheocele, tracheal diverticulum and tracheogenic cyst [5]. Tracheal diverticula can be separated in a congenital and an acquired form, the former being thick walled with cartilaginous rings and smooth muscle, the latter being larger, thin walled and appearing at any level of the trachea. Goo et al. [1] have examined 65 patients with CT evidence of a paratracheal air cyst, lacking histologic or pathologic correlation. The vast majority of these cysts were located on the right paratracheal region at the T2 level. The predilection for the right side is supposed to be due to the lacking support of the left lying esophagus [2]. The point of least resistance seems to be at the level of T2 at the thoracic inlet because it is the transitional point between the extrathoracic and intrathoracic trachea [1]. According to MacKinnon [2], the diverticulum arises by cystic distention of the ducts of mucous glands, finally resulting in a simple epitheliumlined fibrous-walled cyst. The largest vertical diameter in the studies of Goo et al. [1] and MacKinnon [2] were 25 and 30 mm, respectively. Both have observed a positive correlation between chronic cough or lung emphysema and tracheal diverticulum [1,2]. A thread-like communication between the air cyst and trachea was found in only five patients (8%) that underwent
Fig. 2. Sagittal multiplanar reformation through the trachea and the tracheal diverticulum depicting the differences of the extent of the air filled cyst lying in front of the vertebra between expiration (a) and valsalva manoeuvre (b).
P.S. Scherr et al. / European Journal of Radiology Extra 64 (2007) 91–93
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Fig. 3. (A) Tracheal diverticulum in expiration. The connecting duct (arrow) is only slightly visible. (B) Dilatation of the connecting duct (arrow) during valsalva manoeuvre. On both images the esophagus is clearly separated from the lesion.
thick-section CT, and in three (of five) patients that underwent helical CT scanning in thin section (less than 4 mm) [1]. On respiratory dynamic CT, the paratracheal cysts expanded during forced expiration and shrank during inspiration, suggesting a communication between the cyst and the trachea and thus probably representing tracheal diverticulum. This communication could not be seen by means of bronchoscopy (n = 19) or bronchography (n = 4) [1]. “Paratracheal air cyst” is a non-specific term for a broad differential diagnosis of a paratracheal air collection. Besides tracheal diverticulum, this differential diagnosis also includes laryngocele, pharyngocele, Zenker’s diverticulum, apical hernia of the lung and apical paraseptal blebs or bullae [1]. According to Goo et al. [1] cough, sputum, hemoptysis, dyspnea and chest pain are the most common clinical findings. The clinical presentation of our patient with chest pain, dysphagia and odynophagia is very atypical for a tracheal diverticulum, leaving the impression that clinical findings and diverticulum were unrelated one to another. In the literature we found only one reported case presenting with dysphagia [5]. Although we did not prove the diagnosis by histology, the findings on CT scan and additional examinations could narrow the differential diagnosis down to only tracheal diverticulum as cause for the paratracheal air cyst, although the clinical symptoms with collapse, chest pain, dysphagia and odynophagia are not very common for a tracheal diverticulum. The persistence of a paratracheal air cyst in the follow-up CT scan performed in expiration and under valsalva manoeuvre 6 days after the initial scan strengthened our first diagnosis of a tracheal diverticulum. In addition we now could visual-
ize a change in extent between the expiration and valsalva manoeuvre (Fig. 2) and an air bubble in the tracheal wall (Fig. 3), most probably being the origin of the communicating duct. 3. Conclusion A tracheal diverticulum is a rare finding. It is an important differential diagnosis for paratracheal air cysts. The diagnosis is mostly done by ruling out the other differential diagnoses, like laryngocele, pharyngocele, Zenker’s diverticulum, apical hernia of the lung and apical paraseptal blebs or bullae. In many cases a direct communication between a right dorsolateral paratracheal air cyst and the trachea at the thoracic inlet cannot be visualized on standard chest-CT. A follow-up CT scan performed in valsalva manoeuvre – or forced expiration as in another study [1] – is helpful and may inflate the communicating channel to the trachea and may shows changes in extent of the tracheal diverticulum. References [1] Goo JM, Im J, Ahn JM, et al. Right paratracheal air cysts in the thoracic inlet: clinical and radiologic significance. AJR 1999;173:65–70. [2] MacKinnon D. Tracheal diverticula. J Pathol Bacteriol 1953;65:513–7. [3] Soto-Hurtado EJ, Pe˜nuela-Ru´ız L, Rivera-S´anchez I, et al. Tracheal diverticulum: a review of the literature. Lung 2006;184:303–7. [4] Tanaka H, Mori Y, Kurokawa K, et al. Paratracheal air cysts communicating with the trachea: CT findings. J Thor Imag 1997;12:38–40. [5] Djamouri F, Le Pimpec Barthes F, Pheulpin G, et al. Kystes a´eriens” d’origine trach´eale: probl`emes nosologiques et fr´equence r´eelle. Rev Mal Respir 2002;19:523–6.