SUN-393 ACTH-secreting Pheochromocytoma - A Rare Cause of Cushing’s Syndrome

Background: We present a patient with a rare ACTH-secreting pheochromocytoma. Clinical Case: A 47-year-old woman with a 22-year history of hypertension presented to the emergency room complaining of worsening headaches. Despite being on five antihypertensives, she revealed that her blood pressure was still difficult to control. On presentation her BP 187/109mmHg and labs notable for K(+) of 2.4 [3.5-5.0 mmol/L] and a random glucose of 700mg/dL. She was admitted for hypertensive emergency and new onset diabetes. Physical exam was pertinent for anasarca, hyperpigmentation of skin, facial plethora, hirsutism, and acne. Labs were remarkable for a random cortisol of 88 [5.0-25mcg/dL] and ACTH level of 276 [5-46pg/mL]. Cortisol post 1mg dexamethasone was 91 [5.0-25mcg/dL], post 8mg was 88 [5.0-25mcg/dL] and 24-hour free urine cortisol 5863 [3.5-45mcg/24hr]. Pituitary MRI showed a 0.4cm microadenoma and she underwent inferior petrosal sinus sampling that suggested ectopic production of ACTH. A chest CT showed a possible thyroid nodule. Abdominal CT showed bilateral thickened adrenals and a right adrenal nodule 2.9 x 2.0cm in size. Further relevant testing revealed showed: plasma fractionated metanephrine 195 [12-61pg/mL], normetanephrine 195 [18-112pg/mL]. 24-hour urine collections: metanephrine 969 [<400mcg/24hr], normetanephrine 1193 [<900 mcg/24hr], total metanephrines 2162 [<1300mcg/24hr], epinephrine 52 [<21mcg/24hr], norepinephrine 216 [15-80mcg/24hr], dopamine 61 [65-400 mcg/24hr]. Testosterone 225.7 [14-76 ng/dL], DHEAS 1217 [48-244ug/dL], PTH 110 [15-65pg/mL], Calcium 10.35 [8.2-10mg/dL], Vitamin D 25-OH 9 [ng/mL], calcitonin <5.0 [< 7.6pg/mL], CEA 7.9, chromagranin A 55 [<93 ng/mL], gastrin 40 [<100pg/mL], TSH 0.31 [0.27-4.20mclU/mL], and FT4 1.12 [0.93-1.70]. With clear evidence of increased ACTH and catecholamine production she was placed on ketoconazole and phenoxybenzamine, respectively. In attempts to localize the site of excess ACTH production a PET/CT Ga-68 DOTATE was suspicious for a right adrenal pheochromocytoma and left anterior pelvic mass with no evidence of significant SST-R2 expression. PET/CT F-18 F-DOPA exposed a right pheochromocytoma and left lower pelvic mass with mild F-DOPA uptake. She subsequently underwent a right adrenalectomy and postoperatively was treated with hydrocortisone. Need for further antihypertensive and insulin treatment ceased. Her facial roundness, lower extremity weakness and edema resolved. Facial acne persists despite normalization of her testosterone. Conclusion We suggest that patients with Cushing’s Syndrome and uncontrolled HTN be evaluated for ACTH-secreting pheochromocytomas. Although it is a very rare condition, making its diagnosis could be life-saving and achieve clinical remission.