SUN-LB065 A Rare Case of Adrenal Corticomedullary Adenoma: Coexistence of Cushing's Syndrome and Elevated Catecholamines in a Patient With an Incidental Adrenal Mass

Background:Most primary neoplasms of the adrenal gland arise from either adrenal cortical cells or the chromaffin cells of the adrenal medulla. Here we describe a case in which a patient was found to have an incidental adrenal mass with both cortical and medullary components on histology. Clinical Case:A 51-year-old female with DM2 and HTN, presented with an incidental left (L) adrenal mass. She had a 30-pound weight gain over 6 months with complaints of fatigue and easy bruising. CT of her adrenals demonstrated a 3.1 cm L adrenal mass with pre-contrast HU of 31 and washout >50%, suggesting a lipid poor adenoma with a normal contralateral adrenal gland. Her blood pressure was 165/88 mm Hg and BMI was 34. Dorsocervical fat pad enlargement and supraclavicular fullness were noted. A 1 mg dexamethasone suppression test (DST) was abnormal with a dexamethasone (DEX) level- 209 ng/dL (180-550) and cortisol- 8.2 mcg/dL. A late-night salivary test was normal with a cortisol- 0.05 mcg/dl (0.04-0.56). Basal am ACTH and cortisol levels were 24 pg/mL (6-50) and 20.5 mcg/dL (4-22) respectively. Plasma metanephrine- 114 pg/mL (<57), normetanephrine- 300 pg/mL (<148), and total metanephrine- 414 pg/mL (<205) were elevated. DHEA-S, plasma renin and aldosterone were all within normal range. These results suggested that both pheochromocytoma (Pheo) and Cushing’s syndrome (CS) were present. The differential diagnosis included ACTH- secreting Pheo, pituitary CS coexisting with a Pheo, or corticomedullary adenoma. After L adrenalectomy, histological examination showed positive immunohistochemical staining with chromogranin and intermingled adrenocortical components within the same mass, consistent with a corticomedullary adenoma. ACTH immunostaining was positive in a small subpopulation of cells. Post-operatively, the metanephrine levels normalized. The 1 mg DST improved but remained abnormal (DEX level- 245 ng/dL, cortisol- 3.4 mcg/dl). The basal 8 am ACTH and cortisol were 28 pg/mL and 12.7 mcg/dL respectively. She did not require hydrocortisone replacement. Her HTN improved and insulin was discontinued. There were no mutations found in a hereditary Pheo panel (Invitae- 14 genes). Conclusion:Corticomedullary adenomas associated with hypersecretion of cortisol and catecholamines have rarely been reported. All 5 of the previously reported cases have been unilateral with a predilection for females in the third to sixth decades of life(1). In this case, the histologic diagnosis and clinical improvement after adrenalectomy supports a diagnosis of corticomedullary adenoma as the source of hypersecretion of both cortisol and catecholamines. This case demonstrates the importance of screening for CS and Pheo in all patients when evaluating an incidental adrenal mass. Reference:1.Lau, S., Annals of Diagnostic Pathology, 15:185, 2011 Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.