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Mediastinal Parathyroid Cysts
Mediastinal Parathyroid Cysts Ofer Landau, MD, Dean W. Chamberlain, MD, Renee S. Kennedy, MD, F. Griffith Pearson, MD, and Shaf Keshavjee, MD Departments of Thoracic Surgery and Pathology, The Toronto Hospital, University of Toronto, Toronto, Ontario, Canada
Background. Mediastinal parathyroid cysts are a relatively rare clinical entity. The clinical presentation can be quite varied, although most are found incidentally during investigations for esophageal or respiratory symptoms. Methods. We present a review of the literature and describe two instructive cases showing specific clinical findings. The clinical presentation, radiologic and pathologic findings, and treatment of mediastinal parathyroid cysts are discussed. Results. In the first patient, the presenting symptom was increasing hoarseness resulting from paresis of the
right recurrent laryngeal nerve. This case illustrates the rare association of a beign mediastinal parathyroid cyst with unilateral vocal cord palsy. The second patient presented with the more classic findings of progressive dyspnea and stridor related to tracheal compression. Conclusions. Although mediastinal parathyroid cysts are rare and can have varied presentations, thorough investigation can reveal the underlying cyst. Surgical excision is the treatment of choice and can be expected to produce excellent results. (Ann Thorac Surg 1997;63:951–3) © 1997 by The Society of Thoracic Surgeons
P
Upper gastrointestinal endoscopy and laryngoscopy were performed. Extrinsic compression was noted in the midesophagus, and the endoscope could not be advanced. Laryngoscopy revealed right vocal cord paralysis. Bronchoscopy showed marked deviation of the trachea to the left as a result of compression along its right lateral wall. The trachea was narrowed to about a sixth of its normal cross-sectional area at the narrowest point. Fine-needle aspiration yielded 100 mL of clear fluid, which mainly contained macrophages and was considered nondiagnostic. Subsequently the patient was operated on through a right fourth intercostal space thoracotomy. A mass that was 10 cm in diameter was found in the upper mediastinum adherent to surrounding tissues and close to the right lower pole of the thyroid gland. It was causing the trachea and the esophagus to deviate to the left and the recurrent laryngeal nerve to deviate to the right. The mass was surrounded with dense connective tissue and did not have clear anatomic margins. Aspiration of the contents of the mass was required to facilitate its resection. Pathologic examination showed the mass to be a cyst lined mainly by fibrous connective tissue; however, some of the surface was lined by cuboidal epithelial cells with a chief cell morphology. Numerous nests of parathyroid cells, mainly chief cells, were scattered throughout the cyst wall, some of which were admixed with fat (Fig 1C). Immunohistochemical studies showed strongly positive staining of the cells for parathyroid hormone–related peptide and focal weak chromogranin positivity. These findings confirmed the a diagnosis of a benign parathyroid cyst. Three regional lymph nodes were unremarkable histologically. The patient’s postoperative course was uneventful, his calcium level decreased to the normal range (2.38 mmol/L), and the patient was discharged home on the fifth postoperative day.
arathyroid cysts are rare and usually located in the neck with about 10% located in the mediastinum. Most cysts are found incidentally during the search for a cause of either respiratory or esophageal symptoms. To date 17 cases have been reported in the world literature. In this report we describe the clinical presentation, radiologic and pathologic findings, and management of 2 additional cases and review the literature on the subject.
Case Reports Patient 1 A 77-year-old man was admitted to our unit with progressive stridor and dyspnea as well as progressive hoarseness. Five months before he had presented to his family physician because of the recent onset of hoarseness. Nine years earlier he had been treated successfully with radiotherapy for a cervical non-Hodgkin’s lymphoma. He was a nonsmoker and denied any weight loss, anorexia, fever, or chills. The chest x-ray study and computed tomographic scan (Figs 1A, 1B) revealed an 8.8-cm, oval, unilobular mass with a thin, enhancing rim in the superior mediastinum extending into the neck. It appeared to be contiguous with the right lower pole of the thyroid gland. The mass was considerably compressing and displacing the esophagus and moderately displacing and compressing the trachea. Thyroid and gallium scans were both normal. Results of blood tests that included a total blood cell count, thyroid function studies, and blood chemistry tests were found to be within the normal range. The serum calcium level was mildly elevated at 2.87 mmol/L (normal, 2.2 to 2.6 mmol/L). Accepted for publication Nov 6, 1996. Address reprint requests to: Dr Keshavjee, Thoracic Surgery, The Toronto Hospital, 200 Elizabeth St EN10-224, Toronto, ON, Canada M5G 2C4. (e-mail: [email protected]).
© 1997 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
0003-4975/97/$17.00 PII S0003-4975(96)01392-6
952
LANDAU ET AL MEDIASTINAL PARATHYROID CYSTS
Ann Thorac Surg 1997;63:951–3
otherwise unremarkable. A chest x-ray study and computed tomographic scan revealed a homogeneous mass in the left upper mediastinum measuring 11 3 7 cm and severely displacing the trachea (Figs 2A, 2B). A thyroid scan was normal. Results of hematologic and biochemical tests, including the calcium level (2.43 mmol/L), were normal. Preoperative pulmonary function tests showed severe air flow obstruction with fixed increased airway resistance that did not improve after the administration of a bronchodilator. The patient was operated on through a partial upper sternotomy which curved to the left and into the fourth intercostal space. The mass extended well down into the mediastinum, to the level of the left bronchus, causing the trachea to deviate to the right. The lesion had welldefined margins and was resected intact using sharp and blunt dissection. Pathologic examination revealed a thinwalled cyst containing clear, yellow fluid. It was lined by cuboidal to columnar epithelial cells, and scattered groups of parathyroid cells of the chief cell type were found in the cyst wall, confirming the diagnosis of a benign parathyroid cyst (Fig 2C). The patient’s postoperative course was uneventful.
Comment
Fig 1. Patient 1. (A) Chest roentgenogram and (B) computed tomographic scan showing an upper mediastinal mass that causes the esophagus (small arrow) and trachea (large arrow) to deviate to the left. (C) Photomicrograph of the cyst wall showing no perceptible lining epithelium, though parathyroid epithelial tissue, mainly of the chief cell type, is prominent. (Hematoxylin and eosin; 3160 before 52% reduction.)
Patient 2 A 49-year-old, nonsmoking man was referred because of vague upper respiratory tract complaints of several months’ duration. He complained of chest fullness and heaviness and a sensation of being unable to catch his breath. He had been treated unsuccessfully with bronchodilators for presumed asthma. His health history was
Mediastinal parathyroid cysts are rare, there being only 17 previously published cases [1–5]. They usually arise from the inferior glands but can be located in either the upper neck or mediastinum [4], the latter cysts being more common on the right side [3]. The cysts are lined to a variable extent by cuboidal to columnar epithelium, but the diagnosis often rests on the finding of parathyroid elements scattered within the cyst wall. Because the thymus gland and inferior parathyroid glands are both derived from the third pharyngeal pouch, thymic elements may be found in the wall of these cysts as well. In most cases the cysts present as an asymptomatic mass, usually in the fourth to seventh decade of life, and with no predilection for either sex [4, 6, 7]. However, in a review of parathyroid cysts published in 1983, including cysts in both the neck and the mediastinum, Calandra and associates [4] reported that 50% were associated with hyperparathyroidism, as evidenced by hypercalcemia, hypophosphatemia, and elevated parathyroid hormone levels. It has been suggested that those parathyroid cysts which exhibit hormonal function are really adenomas with cystic degeneration [8], although no criteria have been recognized that clearly distinguish one type of cyst from the other. The fluid of parathyroid cysts contains assayable parathyroid hormone, and this may be an aid to diagnosis in the examination of specimens of a cyst obtained by fine-needle aspiration biopsy [9]. In our patients, thorough investigation, which included chest x-ray studies, computed tomographic scans, isotopic scans, hematologic and biochemistry tests, endoscopy, and, in patient 1, fine-needle aspiration biopsy, failed to yield an accurate diagnosis. The first patient was quite unusual in presenting with hoarseness secondary to right vocal cord paresis (which was confirmed by laryngoscopy). The association of vocal cord paresis with
Ann Thorac Surg 1997;63:951–3
LANDAU ET AL MEDIASTINAL PARATHYROID CYSTS
953
of a patient with a cervical parathyroid cyst that was associated with vocal cord paralysis is the most similar to ours. The paresis in our patient may be explained by the pathologic finding of extensive fibrosis with entrapment of the right recurrent laryngeal nerve, combined with chronic traction or compression in relation to the cyst wall. This may have resulted from pressure atrophy and leakage of the cyst content. This patient also exhibited hypercalcemia, with his calcium levels returning to normal after the cyst had been removed. Although considerable parathyroid tissue was present in the cyst wall, its patchy distribution with an occasional admixture of fat, together with the large size and unilocular nature of the cyst, in our view favors a diagnosis of a parathyroid cyst rather than cystic degeneration of an adenoma. The second patient had respiratory symptoms related to tracheal compression, which is the usual presenting picture [3–5]. A thallium-technetium scan, which has been described as a tool for the diagnosis of mediastinal parathyroid cysts [1– 6, 10], was not found to be helpful. Although we encountered no problems perioperatively with this patient’s serum calcium levels, hypocalcemia has been noted in such patients [5] and one should therefore monitor patients carefully for this in the postoperative period. We have contributed 2 cases to the literature on mediastinal parathyroid cysts, with 1 of the patients demonstrating the rare association of vocal cord palsy related to such a cyst. Thus hoarseness in combination with a chest lesion does not always imply malignancy. The second patient illustrates the common picture in which proximal airway obstructive symptoms that arise insidiously are initially misdiagnosed as asthma. Surgical excision of mediastinal parathyroid cysts is the treatment of choice and can be expected to produce excellent results.
References
Fig 2. Patient 2. (A) Chest roentgenogram and (B) computed tomographic scan showing an upper mediastinal mass that causes the esophagus (small arrow) and the trachea (large arrow) to deviate to the right. (C) The cyst is lined by cuboidal epithelium, and parathyroid epithelial tissue is present in the cyst wall. This cyst contained less parathyroid tissue than the cyst in patient 1. (Hematoxylin and eosin; 3160 before 52% reduction.)
a benign mediastinal cyst is exceedingly rare. Usually with the combination of a mediastinal mass and recurrent laryngeal nerve paresis, a diagnosis of malignancy is assumed. The case described by Grey and colleagues [10]
1. Clark OH. Parathyroid cysts. Am J Surg 1978;135:395– 402. 2. Guvendick L, Oo LKM, Roy S, Donaldson LA, Kennedy DD. Management of a mediastinal cyst causing hyperparathyroidism and tracheal obstruction. Ann Thorac Surg 1993;55:167– 8. 3. Cruse CW, Daouk AA. Mediastinal parathyroid cyst: report of a case and review of the world literature. Am J Surg 1978; 135:714– 6. 4. Calandra DB, Shah KH, Prinz RA, et al. Parathyroid cysts: a report of eleven cases including two associated with hyperparathyroid crisis. Surgery 1983;94:887–92. 5. Ramos-Gabatin A, Mallette LE, Bringhurst FR, Draper MW. Functional mediastinal parathyroid cyst: dynamics of parathyroid hormone secretion during cyst aspirations and surgery. Am J Med 1985;79:633–9. 6. Rice TW. Benign neoplasm and cyst of the mediastinum. Semin Thorac Cardiovasc Surg 1992;4:1:25–33. 7. Rosenberg J, Orlando R, Ludwig M, Pyrtek LJ. Parathyroid cysts. Am J Surg 1982;143:473– 80. 8. Rogers LA, Fitter BF, Peete PJ. Parathyroid cyst and the cystic degeneration of parathyroid adenoma. Arch Pathol 1969;88: 476–9. 9. Silverman JF, Khazanie PG, Norris HT, Fore WW. Parathyroid hormone (PTH) assay of parathyroid cysts examined by fine needle aspiration biopsy. Am J Clin Pathol 1986;86:776– 80. 10. Grey AB, Shaw JHF, Anderson NE, Holdaway IM. Parathyroid cyst with recurrent vocal cord paresis. Aust NZ J Surg 1993;63:561–2.
Background. Mediastinal parathyroid cysts are a relatively rare clinical entity. The clinical presentation can be quite varied, although most are found incidentally during investigations for esophageal or respiratory symptoms. Methods. We present a review of the literature and describe two instructive cases showing specific clinical findings. The clinical presentation, radiologic and pathologic findings, and treatment of mediastinal parathyroid cysts are discussed. Results. In the first patient, the presenting symptom was increasing hoarseness resulting from paresis of the
right recurrent laryngeal nerve. This case illustrates the rare association of a beign mediastinal parathyroid cyst with unilateral vocal cord palsy. The second patient presented with the more classic findings of progressive dyspnea and stridor related to tracheal compression. Conclusions. Although mediastinal parathyroid cysts are rare and can have varied presentations, thorough investigation can reveal the underlying cyst. Surgical excision is the treatment of choice and can be expected to produce excellent results. (Ann Thorac Surg 1997;63:951–3) © 1997 by The Society of Thoracic Surgeons
P
Upper gastrointestinal endoscopy and laryngoscopy were performed. Extrinsic compression was noted in the midesophagus, and the endoscope could not be advanced. Laryngoscopy revealed right vocal cord paralysis. Bronchoscopy showed marked deviation of the trachea to the left as a result of compression along its right lateral wall. The trachea was narrowed to about a sixth of its normal cross-sectional area at the narrowest point. Fine-needle aspiration yielded 100 mL of clear fluid, which mainly contained macrophages and was considered nondiagnostic. Subsequently the patient was operated on through a right fourth intercostal space thoracotomy. A mass that was 10 cm in diameter was found in the upper mediastinum adherent to surrounding tissues and close to the right lower pole of the thyroid gland. It was causing the trachea and the esophagus to deviate to the left and the recurrent laryngeal nerve to deviate to the right. The mass was surrounded with dense connective tissue and did not have clear anatomic margins. Aspiration of the contents of the mass was required to facilitate its resection. Pathologic examination showed the mass to be a cyst lined mainly by fibrous connective tissue; however, some of the surface was lined by cuboidal epithelial cells with a chief cell morphology. Numerous nests of parathyroid cells, mainly chief cells, were scattered throughout the cyst wall, some of which were admixed with fat (Fig 1C). Immunohistochemical studies showed strongly positive staining of the cells for parathyroid hormone–related peptide and focal weak chromogranin positivity. These findings confirmed the a diagnosis of a benign parathyroid cyst. Three regional lymph nodes were unremarkable histologically. The patient’s postoperative course was uneventful, his calcium level decreased to the normal range (2.38 mmol/L), and the patient was discharged home on the fifth postoperative day.
arathyroid cysts are rare and usually located in the neck with about 10% located in the mediastinum. Most cysts are found incidentally during the search for a cause of either respiratory or esophageal symptoms. To date 17 cases have been reported in the world literature. In this report we describe the clinical presentation, radiologic and pathologic findings, and management of 2 additional cases and review the literature on the subject.
Case Reports Patient 1 A 77-year-old man was admitted to our unit with progressive stridor and dyspnea as well as progressive hoarseness. Five months before he had presented to his family physician because of the recent onset of hoarseness. Nine years earlier he had been treated successfully with radiotherapy for a cervical non-Hodgkin’s lymphoma. He was a nonsmoker and denied any weight loss, anorexia, fever, or chills. The chest x-ray study and computed tomographic scan (Figs 1A, 1B) revealed an 8.8-cm, oval, unilobular mass with a thin, enhancing rim in the superior mediastinum extending into the neck. It appeared to be contiguous with the right lower pole of the thyroid gland. The mass was considerably compressing and displacing the esophagus and moderately displacing and compressing the trachea. Thyroid and gallium scans were both normal. Results of blood tests that included a total blood cell count, thyroid function studies, and blood chemistry tests were found to be within the normal range. The serum calcium level was mildly elevated at 2.87 mmol/L (normal, 2.2 to 2.6 mmol/L). Accepted for publication Nov 6, 1996. Address reprint requests to: Dr Keshavjee, Thoracic Surgery, The Toronto Hospital, 200 Elizabeth St EN10-224, Toronto, ON, Canada M5G 2C4. (e-mail: [email protected]).
© 1997 by The Society of Thoracic Surgeons Published by Elsevier Science Inc
0003-4975/97/$17.00 PII S0003-4975(96)01392-6
952
LANDAU ET AL MEDIASTINAL PARATHYROID CYSTS
Ann Thorac Surg 1997;63:951–3
otherwise unremarkable. A chest x-ray study and computed tomographic scan revealed a homogeneous mass in the left upper mediastinum measuring 11 3 7 cm and severely displacing the trachea (Figs 2A, 2B). A thyroid scan was normal. Results of hematologic and biochemical tests, including the calcium level (2.43 mmol/L), were normal. Preoperative pulmonary function tests showed severe air flow obstruction with fixed increased airway resistance that did not improve after the administration of a bronchodilator. The patient was operated on through a partial upper sternotomy which curved to the left and into the fourth intercostal space. The mass extended well down into the mediastinum, to the level of the left bronchus, causing the trachea to deviate to the right. The lesion had welldefined margins and was resected intact using sharp and blunt dissection. Pathologic examination revealed a thinwalled cyst containing clear, yellow fluid. It was lined by cuboidal to columnar epithelial cells, and scattered groups of parathyroid cells of the chief cell type were found in the cyst wall, confirming the diagnosis of a benign parathyroid cyst (Fig 2C). The patient’s postoperative course was uneventful.
Comment
Fig 1. Patient 1. (A) Chest roentgenogram and (B) computed tomographic scan showing an upper mediastinal mass that causes the esophagus (small arrow) and trachea (large arrow) to deviate to the left. (C) Photomicrograph of the cyst wall showing no perceptible lining epithelium, though parathyroid epithelial tissue, mainly of the chief cell type, is prominent. (Hematoxylin and eosin; 3160 before 52% reduction.)
Patient 2 A 49-year-old, nonsmoking man was referred because of vague upper respiratory tract complaints of several months’ duration. He complained of chest fullness and heaviness and a sensation of being unable to catch his breath. He had been treated unsuccessfully with bronchodilators for presumed asthma. His health history was
Mediastinal parathyroid cysts are rare, there being only 17 previously published cases [1–5]. They usually arise from the inferior glands but can be located in either the upper neck or mediastinum [4], the latter cysts being more common on the right side [3]. The cysts are lined to a variable extent by cuboidal to columnar epithelium, but the diagnosis often rests on the finding of parathyroid elements scattered within the cyst wall. Because the thymus gland and inferior parathyroid glands are both derived from the third pharyngeal pouch, thymic elements may be found in the wall of these cysts as well. In most cases the cysts present as an asymptomatic mass, usually in the fourth to seventh decade of life, and with no predilection for either sex [4, 6, 7]. However, in a review of parathyroid cysts published in 1983, including cysts in both the neck and the mediastinum, Calandra and associates [4] reported that 50% were associated with hyperparathyroidism, as evidenced by hypercalcemia, hypophosphatemia, and elevated parathyroid hormone levels. It has been suggested that those parathyroid cysts which exhibit hormonal function are really adenomas with cystic degeneration [8], although no criteria have been recognized that clearly distinguish one type of cyst from the other. The fluid of parathyroid cysts contains assayable parathyroid hormone, and this may be an aid to diagnosis in the examination of specimens of a cyst obtained by fine-needle aspiration biopsy [9]. In our patients, thorough investigation, which included chest x-ray studies, computed tomographic scans, isotopic scans, hematologic and biochemistry tests, endoscopy, and, in patient 1, fine-needle aspiration biopsy, failed to yield an accurate diagnosis. The first patient was quite unusual in presenting with hoarseness secondary to right vocal cord paresis (which was confirmed by laryngoscopy). The association of vocal cord paresis with
Ann Thorac Surg 1997;63:951–3
LANDAU ET AL MEDIASTINAL PARATHYROID CYSTS
953
of a patient with a cervical parathyroid cyst that was associated with vocal cord paralysis is the most similar to ours. The paresis in our patient may be explained by the pathologic finding of extensive fibrosis with entrapment of the right recurrent laryngeal nerve, combined with chronic traction or compression in relation to the cyst wall. This may have resulted from pressure atrophy and leakage of the cyst content. This patient also exhibited hypercalcemia, with his calcium levels returning to normal after the cyst had been removed. Although considerable parathyroid tissue was present in the cyst wall, its patchy distribution with an occasional admixture of fat, together with the large size and unilocular nature of the cyst, in our view favors a diagnosis of a parathyroid cyst rather than cystic degeneration of an adenoma. The second patient had respiratory symptoms related to tracheal compression, which is the usual presenting picture [3–5]. A thallium-technetium scan, which has been described as a tool for the diagnosis of mediastinal parathyroid cysts [1– 6, 10], was not found to be helpful. Although we encountered no problems perioperatively with this patient’s serum calcium levels, hypocalcemia has been noted in such patients [5] and one should therefore monitor patients carefully for this in the postoperative period. We have contributed 2 cases to the literature on mediastinal parathyroid cysts, with 1 of the patients demonstrating the rare association of vocal cord palsy related to such a cyst. Thus hoarseness in combination with a chest lesion does not always imply malignancy. The second patient illustrates the common picture in which proximal airway obstructive symptoms that arise insidiously are initially misdiagnosed as asthma. Surgical excision of mediastinal parathyroid cysts is the treatment of choice and can be expected to produce excellent results.
References
Fig 2. Patient 2. (A) Chest roentgenogram and (B) computed tomographic scan showing an upper mediastinal mass that causes the esophagus (small arrow) and the trachea (large arrow) to deviate to the right. (C) The cyst is lined by cuboidal epithelium, and parathyroid epithelial tissue is present in the cyst wall. This cyst contained less parathyroid tissue than the cyst in patient 1. (Hematoxylin and eosin; 3160 before 52% reduction.)
a benign mediastinal cyst is exceedingly rare. Usually with the combination of a mediastinal mass and recurrent laryngeal nerve paresis, a diagnosis of malignancy is assumed. The case described by Grey and colleagues [10]
1. Clark OH. Parathyroid cysts. Am J Surg 1978;135:395– 402. 2. Guvendick L, Oo LKM, Roy S, Donaldson LA, Kennedy DD. Management of a mediastinal cyst causing hyperparathyroidism and tracheal obstruction. Ann Thorac Surg 1993;55:167– 8. 3. Cruse CW, Daouk AA. Mediastinal parathyroid cyst: report of a case and review of the world literature. Am J Surg 1978; 135:714– 6. 4. Calandra DB, Shah KH, Prinz RA, et al. Parathyroid cysts: a report of eleven cases including two associated with hyperparathyroid crisis. Surgery 1983;94:887–92. 5. Ramos-Gabatin A, Mallette LE, Bringhurst FR, Draper MW. Functional mediastinal parathyroid cyst: dynamics of parathyroid hormone secretion during cyst aspirations and surgery. Am J Med 1985;79:633–9. 6. Rice TW. Benign neoplasm and cyst of the mediastinum. Semin Thorac Cardiovasc Surg 1992;4:1:25–33. 7. Rosenberg J, Orlando R, Ludwig M, Pyrtek LJ. Parathyroid cysts. Am J Surg 1982;143:473– 80. 8. Rogers LA, Fitter BF, Peete PJ. Parathyroid cyst and the cystic degeneration of parathyroid adenoma. Arch Pathol 1969;88: 476–9. 9. Silverman JF, Khazanie PG, Norris HT, Fore WW. Parathyroid hormone (PTH) assay of parathyroid cysts examined by fine needle aspiration biopsy. Am J Clin Pathol 1986;86:776– 80. 10. Grey AB, Shaw JHF, Anderson NE, Holdaway IM. Parathyroid cyst with recurrent vocal cord paresis. Aust NZ J Surg 1993;63:561–2.