A GIANT Asymptomatic Pheochromocytoma

Presentation Number: SAT 394
Date of Presentation: April 1st, 2017

Sravanthi Madala*1 and Ricardo Rafael Correa2
1Warren Alpert Medical School of Brown University, East Providence, RI, 2Brown University, Warren, RI

Abstract

Background: While incidental pheochromocytomas (pheo) can be asymptomatic, active catecholamine-secreting pheos can be devastating when symptoms such as tachycardia, paroxysmal hypertension, sweating and headaches are present. A complete lack of symptoms in the setting of a giant pheo with extremely high catecholamine levels is unusual, especially in post-biopsy setting.

Case: A 41 year old African-American male with past history of polycythemia vera, hyperlipidemia and CAD was incidentally found to have a palpable non-tender left-sided abdominal mass in setting of normotension by his hematologist during a routine follow up visit. A CT abdomen/pelvis revealed a left retroperitoneal 14.8 x 12.0 x 17.0 cm mixed cystic and solid mass of uncertain origin with calcific focus, displacing the surrounding organs. An FNA biopsy was done without complication, which showed neuroendocrine tumor consistent with pheo/paraganglioma with atypical features. Biopsy sample stained positive for chromogranin A, synaptophysin, CD56, GATA3 and focal positivity for S100. There was no increase in mitotic activity or necrosis and Ki-67 proliferation index was <5%. At this point, the patient was referred to endocrinology and endocrine surgery services. Home medications included carvedilol 3.125mg BID and Lisinopril 2.5mg daily for cardioprotection in setting of CAD. The patient denied ever having hypertension, dizzy spells, sweating, palpitations, headaches, chest pain, fainting, or vertigo. No family history of pheo/para. Biochemical work up revealed 24-hour urine: metanephrines 2410 (52-341 mcg/24hr), normetanephrines 3670 (88-444 mcg/24hr), norepinephrine 38 (15-80 mcg/24hr), epinephrine 25 (0-20 mcg/24hr) and dopamine 7874 (65-400 mcg/24hr); plasma: metanephrine 750 (<57 pg/mL), normetanephrines 3519 (<148 pg/mL), norepinephrine 751 (0-600 pg/mL), epinephrine 86 (0-90 pg/mL), and dopamine <20 (0-35 pg/mL). He was started on phenoxybenzamine for blockage and underwent adrenalectomy without complications. Pathology revealed a 20 cm pheochromocytoma without extension into surrounding soft tissue or lymph node involvement.

Conclusion: This case illustrates the rare presentation of a giant asymptomatic hormone-secreting pheo. While large pheochromocytomas can be asymptomatic, they are usually known to have lower secretory function. There is very little literature on any pheos greater than 20 cm with elevated hormone levels that are asymptomatic. Interestingly, this patient did not go into catecholamine storm while on beta blocker therapy without simultaneous alpha blockade or while the mass was manipulated during initial biopsy, prior to its classification as a pheo. The extremely large size of the tumor, degree of metabolic activity and absence of end organ damage or metastatic disease, as seen in this patient, may be attributable to biochemically inactive hormone production.

 

Nothing to Disclose: SM, RRC