Endocrine Abstracts

Introduction: Pheochromocytomas and extra-adrenal paragangliomas are rare neuroendocrine tumors, with a peak incidence between the 3rd–5th decades of life and about 10% are malignant. Although they have the same radiographic and histologic characteristics of their benign counterpart, malignant pheochromocytomas are diagnosed by the presence of local invasion or metastatic tumor in the non-chromaffin tissues, and offer a poorer prognosis. Treatment is typically extirpative surgery, although MIBG-radiotherapy and chemotherapy have been offered in nonsurgical cases.

Case Report: An 83-year-old man with history of diabetes mellitus and hypertension presented abdominal pain, anorexia and weight loss. An abdominal CT revealed a large, hypocaptant and heterogenous neoformative lesion of left adrenal gland, 48×58 mm, and adjacent metastatic adenomegaly with 18 mm. He was then referred to our Endocrine Department. Imaging study was repeated and revealed an additionally left renal mass, on the posterior face, exophytic, with 40×13×38 mm, suspected for metastasis. Biochemical diagnosis of pheochromocytoma was established by a marked increase of urinary catecholamines and fractionated metanephrines: norepinephrine 1222 (<97) μg/24 h, epinephrine 106 (<27) μg/24 h and dopamine 1166 (<500) μg/24 h; normetanephrines 3711 (<390) μg/24 h and metanephrines 1226 (<320) μg/24 h; vanillylmandelic acid (VMA) was 29.3 (1.4–6.5) mg/24 h. ¹²³I-MIBG scintigraphy was performed and evidenced left adrenal gland lesion compatible with pheochromocytoma, without uptake on left renal mass. The patient started alpha-adrenergic blockade with phenoxybenzamine (10+10 mg/day) and 6 weeks later underwent exploratory laparotomy surgery, with left adrenalectomy and nefrectomy. Histological examination confirmed malignant pheochromocytoma diagnosis and the patient maintains close surveillance.

Conclusion: Malignant pheochromocytomas present clinicians with three major challenges: scarcity, complexity of characterization, and heterogeneous behavior and prognosis.