Carcinoid tumor of the jugulo-tympanic region

Increased levels of 5-hydroxyindole acetic acid (5-HIAA) were found in a patient with a tumor arising in the middle ear. Iodine-123-metaiodobenzylguanidine ([123I]MIBG) scintigraphy and biochemical analysis showed evidence of serotonin production by the tumor. Immunohistochemistry of the tumor showed reactivity with antibodies directed against serotonin, chromogranin, leu-7 and neuron-specific enolase; S-100, met-enkephalin, leu-enkephalin and glial fibrillary acid protein were negative. This case suggests a close relationship between functioning paragangliomas and carcinoid tumors because a strong clinical and endocrinological resemblance exists. The hormonal activity found is discussed in relation to extra-adrenal paragangliomas. We recommend urinary screening not only for detection of increased levels of catecholamines, but also of 5-HIAA in all patients with paragangliomas of the head and neck. When elevated levels are found, [123I]MIBG scintigraphy should be performed to localize the areas of increased uptake in or outside the head and neck region.