SAT588 Cushing’s Syndrome Due To Ectopic ACTH Secretion From Ovarian Teratomas

Disclosure: Y. Kang: None. M.S. Gildenberg: None. B.J. Quade: None. R.A. Blair: None. Background: Approximately 9-18% of Cushing’s syndrome (CS) cases are secondary to ectopic ACTH secretion, most commonly from sources in the lung or mediastinum. However, ACTH-producing tumors are rarely found in distant organs, occasionally making the localization and management challenging. Clinical Case: A 32-year-old woman with class 3 obesity, hidradenitis suppurativa, anxiety, and depression experienced atraumatic pelvic and sacral fractures. DXA scan result showed Z-scores of -3.1 in the lumbar spine, -2.6 in the femur neck, and -0.5 in the total hip. She reported a steady weight-gain of 250 lbs over 7 years despite lifestyle modifications and liraglutide. On examination, she had a round face with plethora, acne, violaceous abdominal striae, and dorsocervical fat pad. Laboratory findings revealed elevated midnight salivary cortisol levels of 453 and 424 ng/dL (n: <100 ng/dL), elevated 24-hour urine cortisol levels of 254 and 741 (n: 3.5-45 mcg), and an abnormal 1 mg dexamethasone suppression test (DST) result at 15.1 ug/dL. AM plasma ACTH and cortisol levels were 190 pg/mL and 18.5 ug/dL, suggesting ACTH-dependent hypercortisolism. The plasma cortisol level after an 8 mg DST was unsuppressed at 13.1 ug/dL with a dexamethasone level of 3,380 ng/dL (n: >800 ng/dL). Abdominal CT and MRI scans showed large bilateral adnexal masses measuring up to 13.7 cm on the left and 9.3 cm on the right, with heterogeneous solid and cystic components, consistent with mature cystic ovarian teratomas. DOTATE-PET scan did not show any areas of increased uptake. The patient underwent a laparoscopic right cystectomy and left oophorectomy, with immediate drop in cortisol (1.6 ug/dL) and signs of adrenal insufficiency post-operatively, requiring hydrocortisone replacement. After holding hydrocortisone for 24 hours prior to laboratory assessment one week post-operatively, her ACTH and cortisol were undetectable, reflecting successful source removal. Pathology report showed neuroendocrine tumor with pituitary differentiation with positive ACTH immunohistochemical staining and Ki-67 proliferative index of 22.6% on the left adnexal mass, and a mature cystic teratoma on the right. Conclusion: Although rare, pituitary differentiation of ovarian teratomas should be considered as a possible source of ectopic ACTH secretion in CS patients without obvious sources identified in commonly involved organs. Presentation: Saturday, June 17, 2023