Paraganglioma of the thyroid: Two cases that clarify and expand the clinical spectrum

Background. Paragangliomas (PGs) can, on rare occasions, arise within the t hyroid parenchyma presumably from displaced laryngeal paraganglia. On the b asis of a limited number of reported cases, thyroid PGs invariably affect w omen, they are always benign. and they are usually mistaken for some other more common thyroid lesion. Methods. We describe the histopathologic features, immunohistochemical find ings, and clinical characteristics of two thyroid PGs. Results. One tumor was incidentally discovered in a 55-year-old man during evaluation of a carotid bruit. The other tumor aggressively invaded the tra chea and esophagus of a 52-year-old woman with a presumed long-standing nod ular goiter. In both cases, the initial pathologic evaluation suggested med ullary thyroid carcinoma. Both patients are alive without recurrent disease after surgical resection. Conclusions. These cases emphasize the need to consider PG in the different ial diagnosis of neuroendocrine thyroid tumors, even in those tumors involv ing men or behaving in a locally aggressive fashion. Failure to do so carri es grave implications regarding patient prognosis and management. (C) 2000 John Wiley & Sons, Inc.