MALIGNANT PHEOCHROMOCYTOMA IN MULTIPLE ENDOCRINE NEOPLASIA TYPE 2B SYNDROME - CASE-REPORT AND REVIEW OF THE LITERATURE

A malignant behavior (i.e., distant metastatic spread) has been record ed in 3-4% of pheochromocytomas occurring in the context of multiple e ndocrine neoplasia type PA syndrome, but has never been documented in patients with the type Pa form. In this report we describe a case of m alignant pheochromocytoma arising in the latter syndrome setting. The patient, a white young male, had the full-blown syndrome, including mu lticentric, bilateral medullary thyroid carcinoma metastatic to region al lymph nodes, mucosal neuromas, digestive ganglioneuromatosis, marfa noid habitus, and bumpy lips. Three and a half years after surgical re section of an apparently benign adrenal pheochromocytoma he developed widespread osseous metastases. The presence of hypertensive crises and high urinary catecholamine excretion rates, coupled to moderate hyper calcitoninemia, normal circulating carcinoembryonic antigen levels, ne gative whole-body Tc-99m-(V) dimercaptosuccinic acid scan, and absence of neck or mediastinal disease by magnetic resonance imaging, proved that the metastases were from his previous adrenal and not thyroid tum or. Furthermore, since the bone metastases strongly accumulated I-131- metaiodobenzylguanidine, several courses of the radiocompound were giv en, which resulted In an objective, though partial, tumor regression.