Asian Cardiovasc Thorac Ann 2007;15:e49-e51
© 2007 Asia Publishing EXchange Ltd
Mediastinal Aortosympathetic Paraganglioma: Report of Two Cases
Ricard Ramos, MD,
Juan Moya, PhD,
Rosa Villalonga, PhD1,
Ricard Morera, MD,
Gerardo Ferrer, PhD
Department of Thoracic Surgery
1 Department of Anesthesiology, Hospital Universitari de Bellvitge, Barcelona, Spain
For reprint information contact: Ricard Ramos, MD, Tel: 34 67 045 5480, Fax: 34 93 338 4678, Email: Ricardramos{at}ub.edu, Servei de Cirurgia Toràcica, Hospital Universitari de Bellvitge, Feixa Llarga s/n, 08907 - L’Hospitalet de Llobregat, Barcelona, Spain.
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ABSTRACT
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Thoracic paragangliomas or extra-adrenal pheochromocytomas are uncommon neoplasms that may arise from the extra-adrenal paraganglia. Paragangliomas arising in the anterior mediastinum are most frequent and are related to the base of the heart. Paragangliomas of the posterior mediastinum are most infrequent, and arise from aorticosympathetic paraganglia. We present two cases of posterior mediastinum paraganglioma. Complete tumor resection was done through posterolateral thoracotomy. The diagnosis of aorticosympathectic paraganglioma was established by histologic examination.
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INTRODUCTION
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Paraganglioma is a neuroendocrine cell neoplasm arising from paraganglia which are widely dispersed groups of specialized neural crest cells. They are usually nonfunctioning, but in a few cases they can be functioning tumors. They are slow-growing tumors and rarely develop into malignancy. We report two cases of intrathoracic paraganglioma arising from aorticosympathetic paraganglion. One of them is a functioning paraganglioma and the other is a nonfunctioning paraganglioma of the posterior mediastinum.
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CASE REPORTS
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CASE 1
A 43-year-old man was admitted with left-sided cardiac failure. On admission his blood pressure was 170/90 mm Hg. A chest film disclosed a parahilar mass on the right side and computerized tomography (CT) scan showed a paraspinal mass on the right side that eroded the 6th and 7th ribs, and the 6th thoracic vertebra. The concentration of urinary vanillylmandelic acid was 138 µmol·L–1 [normal value (NV): 15–37.8 µmol·L–1], urinary norepinephrine 8,978 nmol·L–1 (NV: 118–591 nmol·L–1), urinary epinephrine 986 nmol·L–1 (NV: < 295 nmol·L–1), and urinary metanephrines 21.3 µmol·L–1 (NV: < 6.6 µmol·L–1). After alpha and beta-adrenergic blockade a thoracic angiogram by intra-arterial digital substraction revealed a highly vascularized tumor supplied primarily by dilated 5th, 6th, and 7th intercostal arteries that were selectively catheterized and then embolized with gel foam (Figure 1
). The blood supply via these arteries was thereby occluded. The patient remained asymptomatic throughout the procedure, although blood pressure rose after the embolizations. Two days later a right posterolateral thoracotomy through the 5th intercostal space identified a retropleural mass, measuring 8 x 5 x 6 cm. The tumor was detached from the vertebral body, but it was firmly fixed to the 6th and 7th ribs, which were partly excised with the mass. Complete macroscopic removal of the tumor was performed. Nitroprusside was needed during the operation to maintain blood pressure at safe levels and 1 L of blood was administered. Histological examination showed a mostly encapsulated pheochromocytoma; the ribs and apophysis traversa of the 6th vertebra were found to be invaded by the tumor.
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Figure 1. Posteroanterior radiograph and thoracic angiogram revealed a highly vascularized tumor supplied by intercostal arteries.
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CASE 2
An asymptomatic 69-year-old woman presented with a history of hypertension of approximately 6 years duration and pulmonary tuberculosis 20 years ago. She was found to have a mediastinal mass on routine chest X-Ray. Physical examination was normal. Posteroanterior, lateral X-Ray and CT scan revealed a 6 cm lesion in the left posterosuperior mediastinum without malignant characteristics (Figure 2). Routine laboratory investigations showed nothing abnormal. The barium meal was normal. A right posterolateral thoracotomy was performed via the 5th intercostal space, and a large, encapsulated tumor mass of high vascularity and significant consistency was found adhering posteriorly to the spine, aorta, and under the parietal pleura. Resection was made difficult by abundant bleeding. No change in blood pressure occurred during the operative procedure. The patient had an uneventful postoperative course and was discharged on the 10th postoperative day. Pathologic examination showed well-defined nests of polygonal cells separated by highly vascularized fibrous septa. The cells had prominent Golgi apparatus and numerous mitochondria. Very few mitotic figures were identified and none was atypical. Immunohistochemistry showed a strong cytoplasmic staining for chromogranin and synaptophysin and a low number of S-100 protein-positive sustentacular cells. After surgery an iodine 123-metaiodobenzyl-guanidine (123I-MIBG) scan and gallium-67 citrate scintigram were negative.
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DISCUSSION
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Various terms have been used for tumors arising from extra-adrenal paraganglia. Glemmer and Grimley1 suggested that the extra-adrenal portion of the paraganglion system should be grouped on the basis of anatomic distribution, microscopic structure and innervation: I° Intravagal, II° Branchiomeric, III° Aorticosympathetic and IV° Visceral. The tumors in the cases presented here can be classified as group III° aorticosympathetic paraganglioma according to this classification.
Intrathoracic paragangliomas are unusual. Paragangliomas arising in the anterior mediastinum are most frequent and are related to the base of the heart. The paragangliomas of the posterior mediastinum are the most infrequent, and arise from aorticosympathetic paraganglia. These paragangliomas have been associated with a less aggressive course, older age group, less incidence of association with other paragangliomas, and more frequent functional manifestations. Multiple tumors may develop synchronously or asynchronously after successful removal of the first lesion.2,3,4
The diagnosis is difficult: patients with functioning paragangliomas can manifest excessive sweating, hypertension, headaches, tachycardia and other symptomatology related to the secretion of epinephrine and norepinephrine, as in Case 1. This symptomatology can help the diagnosis and it can be confirmed with biochemical probes. The nonfunctioning tumors are asymptomatic and can cause neurological symptoms, chest discomfort or symptomatic relationship with metastasis in the malignant paraganglioma.5 Diagnosis is usually achieved through computed tomography and magnetic resonance imaging (MRI). Localization by 123I-MIBG scintigraphy is useful when the patient has a functioning tumor, adrenal or extra-adrenal pheochromocytomas.
Functional investigation was not performed in Case 2 as the diagnosis was not suspected, although the patient had been hypertensive for approximately 6 years. In Case 1 the symptomatology and chest X-Ray were more suggestive of paraganglioma and urinary catecholamines and 123I-MIBG scan were performed. In Case 1, we performed preoperative arterial embolization. Selective angiography and preoperative selective embolization can be considered, with adjuvant treatment in selected cases, to decrease bleeding and catecholamine secretion during surgical removal.6
The treatment is surgical removal, as in our cases, however radiotherapy, chemotherapy or 123I-MIBG can be considered in cases of incomplete excision or metastasic disease. When a functional tumor is removed, the patient must receive preoperative alpha-blockade and beta-blockade to prevent hypertensive crises. In Case 1 nitroprusside was needed during the operation. Although there are histological findings suggestive of malignancy, follow-up examination of the patient for detected synchronous or metachronous metastases confirms the malignancy and the prognosis.7,8
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REFERENCES
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- Glenner GG, Grimley PM. Tumors of the extra-adrenal paraganglion system (including chemoreceptors). In: Firminger HI, ed. Atlas of tumor pathology, series 2, fascicle 9. Washington, DC: Armed Forces Institute of Pathology, 1974;1–90.
- Evora PR, Bongiovani HL, Sgarbieri RN, Ribeiro PJ, Pereira LC, Moraes MM, et al. Nonfunctioning parganglioma of the posterior mediastinum. Case report. Scand J Thorac Cardiovasc Surg 1988;22:295–7.[Medline]
- Szukics B, Ritter MM, Rau HG, Engelhardt D. Resection of a branchiomeric paraganglioma at a rare extrapulmonary location. Ann Thorac Surg 2000;70:1725–7.[Abstract/Free Full Text]
- Kwon HJ, Park JH, Jin GY, Chung MJ, Lim ST, Kim MH, et al. Posterior mediastinal paraganglioma with bilateral adrenal pheochromocytoma. Respir Med 2004;98:574–6.[Medline]
- Olson JL, Salyer WR. Mediastinal paragangliomas (aortic body tumor): a report of four cases and a review of the literature. Cancer 1978;41:2405–12.[Medline]
- Montana E, Montana X, Morera R, Canto A, Villalonga R, Ligorria C, et al. Functioning paraganglioma (pheochromocytoma) of the thorax: preoperative embolization. J Thorac Cardiovasc Surg 1990;100:626–8.[Medline]
- Odze R, Begin LR. Malignant paraganglioma of the posterior mediastinum. A case report and review of the literature. Cancer 1990;65:564–9.[Medline]
- Plaza JA, Wakely PE Jr, Moran C, Fletcher CD, Suster S. Sclerosing paraganglioma: report of 19 cases of an unusual variant of neuroendocrine tumor that may be mistaken for an aggressive malignant neoplasm. Am J Surg Pathol 2006;30:7–12.[Medline]
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ABSTRACT
INTRODUCTION
