Paraganglioma of the mediastinum is an extremely uncommon neoplasm, and the concurrent finding of cystic changes has yet to be reported in the literature. We report a case of a 43-year-old man presenting with chest pain and left arm paresthesias. Imaging studies revealed a well-defined cystic lesion located in the anterior mediastinum, with the patient undergoing subsequent surgical resection of the mass. Grossly, the heterogenous mass measured 6.0 × 3.6 × 1.7 cm, with prominent cystic spaces and scattered solid areas. Microscopic examination revealed pseudocystic spaces with proliferation of large epithelioid cells with abundant eosinophilic cytoplasm, moderate pleomorphic nuclei, and prominent nucleoli, in a nested pattern of growth along the cysts walls. Immunohistochemical stains showed strong positivity for chromogranin, synaptophysin, and CD56 in the epithelioid cells, with negative staining for cytokeratin AE1/AE3, confirming the diagnosis of paraganglioma. S-100 was positive in the intervening sustentacular cells throughout the tumor. Cystic paraganglioma of the anterior mediastinum is a rare neoplasm, which , to our knowledge, has not yet been reported in the English literature, and should be added to the differential diagnosis of cystic lesions of the mediastinum.
ABSTRACT