MON-531 - Coexistence of Pheochromocytoma and Mild Autonomous Cortisol Secretion in the Same Adrenal Gland

Background: Pheochromocytomas are catecholamine-secreting tumors originating from the adrenal medulla. Cortical adenomas, which derive from cortical cells, can be either nonfunctional or productive, secreting aldosterone or cortisol. Adrenal incidentaloma is a common imaging finding. However, coexistence of pheochromocytoma and cortical adenoma in the same gland is rare. Here we report a case of concomitant pheochromocytoma and cortisol-secreting adenoma.

Clinical

Case: A 2.4 cm right adrenal nodule was found incidentally on a CT scan in a 62-year-old man with history of hypertension, insulin-dependent diabetes mellitus, and benign prostatic hyperplasia. The patient had experienced palpitations, diaphoresis, and headaches for multiple years. Plasma metanephrine 88 [nl 0–57 pg/mL] and normetanephrine 700 [nl 0-148 pg/mL] were elevated, as well as 24-hour urine metanephrine 554 [nl 90–315 μg/24h] and normetanephrine 2,061 [nl 122–676 μg/24h]. Renin activity and plasma aldosterone level were normal. Cortisol was not suppressed by 1-mg and 8-mg dexamethasone, 3.2 [nl < 1.8 μg/dL] and 5.0 [nl < 1.0 μg/dL] accordingly. ACTH 8 [nl 6–50 pg/mL] and DHEA-S 31 [nl 20-217 mcg/dL] were at the low normal end. Both pheochromocytoma and mild autonomous cortisol secretion were considered. Although there was no uptake on MIBG scan, an intensely avid 2.5-cm right adrenal nodule showed on PET-CT Ga68-Dotate, supporting the diagnosis of pheochromocytoma. The patient underwent right adrenalectomy with preoperative alpha blockade. Pathology confirmed 2.6 cm pheochromocytoma with an adjacent 1 cm cortical adenoma. Postoperatively, he no longer required anti-hypertensive medication or insulin. He did not receive glucocorticoid replacement and denied symptoms of adrenal insufficiency. Repeated plasma metanephrines were normal, morning cortisol being 11.3 [nl 4-22 μg/dL] and was suppressed to 1.2 μg/dL by 1-mg dexamethasone. Remission of excess catecholamine and hypercortisolism was successfully achieved.

Conclusion: PET-CT Ga68-Dotate is a sensitive imaging test for detecting pheochromocytomas. When evaluating adrenal incidentalomas with mixed biochemical findings, clinicians should consider coexistence of cortical adenomas and pheochromocytomas, as 4% of pheochromocytoma may have synchronous ipsilateral adrenocortical adenomas according to a prior study (1).

References:
(1) Hasassri ME, Pandian TK, Bobr AA, Bancos I, Young WF Jr, Richards ML, Farley DR, Thompson GB, McKenzie TJ. Pheochromocytoma with Synchronous Ipsilateral Adrenal Cortical Adenoma. World J Surg. 2017 Dec;41(12):3147-3153. doi: 10.1007/s00268-017-4110-8. PMID: 28762170

Keywords: adrenal incidentaloma, pheochromocytoma, adenoma

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