(8.12) A Case of Asymptomatic, Biochemically Active Pheochromocytoma

Originating either in the adrenal medulla or paraganglia, pheochromocytomas are rare catecholamine producing tumors. Typical symptoms include paroxysmal hypertension, severe headaches, palpitations, and sweating resulting from hormone excess. On rare occasions, the tumor remains inert until a stress-inducing event prompts the release of catecholamines.


Case(s) Description : A 58-year-old female patient with a history of hyperlipidemia presented to the hospital after a syncopal episode. Patient reported a history of diarrheal illness for a week prior to presentation. She denied any other acute concerns including chest pain, palpitations, shortness of breath, diaphoresis, headaches, or visual changes. Vitals on arrival were within normal limits. Labs on arrival showed several electrolyte abnormalities including hyponatremia, hypokalemia and hypochloremia due to recent viral gastroenteritis. Abdominal imaging showed a large, complex 6.7 x 6.3 x 5.5 cm lesion arising from the left adrenal gland. A complete biochemical work up showed higher elevation in metanephrine compared to normetanephrine which is consistent with an adrenal pheochromocytoma. Elevations in gastrin, vasoactive intestinal peptide and somatostatin were also observed. She was started on alpha blockade followed by beta blockade in preparation for open left adrenalectomy. After a successful adrenalectomy postsurgical biochemical work up showed normalization of metanephrine, normetanephrine, vasoactive intestinal peptide, gastrin, and somatostatin levels. Surgical pathology confirmed pheochromocytoma. Prior to discharge patient was scheduled for Endocrinology and surgical oncology follow ups, with pending genetic work up.

Discussion : Although the clinical presentation of pheochromocytoma is varied based on the biochemical activity of tumor, the most common presentation is paroxysmal hypertension, headache, palpitation and hyperhidrosis. The typical symptoms are due to excess release and high levels of circulating catecholamines. Orthostatic hypotension can be seen due to desensitization of adrenergic receptors by the chronic excess of catecholamines. This case is unique because despite the high levels of catecholamines, the patient remained asymptomatic. Pheochromocytomas have also been found to secret neuropeptide Y or chromogranin A, and on rare occasions, may release vasoactive intestinal peptide, serotonin, or calcitonin. The elevated levels of gastrin, somatostatin and vasoactive intestinal peptide in this patient, which normalized after adrenalectomy, is suspicious of pheochromocytoma producing multiple hormones in addition to catecholamines.