FRI223 Ectopic ACTH Syndrome

Disclosure: S. Mallesara Sudhakar: None. E.S. Story: None. Introduction: Ectopic ACTH Syndrome (EAS) is caused by hypercortisolism from extra-hypophysial tumors. EAS accounts for 10-15 % of Cushing’s Syndrome. Case 1: A 36 year old male with recently diagnosed stage IV well differentiated grade 2 neuroendocrine tumor (NET) of the pancreas with liver metastases developed new hypertension, hyperglycemia, hypokalemia, metabolic alkalosis, fatigue and muscle weakness. There were no obvious signs of Cushing’s Syndrome. ACTH was 679 pg/ml, cortisol 120 ug/ml. MRI pituitary was normal. He required 4 antihypertensives, insulin, and metyrapone was initiated for hypercortisolism. Due to difficulty obtaining medications during the COVID pandemic, intolerance to therapies and lack of improvement in clinical symptoms, decision was made to perform laparoscopic bilateral adrenalectomy. He was started on hydrocortisone and fludrocortisone. Pathology revealed diffuse adrenal hyperplasia. Post-surgery he improved dramatically and was able to discontinue antihypertensives and insulin. Chemotherapy for the underlying tumor was discontinued due to cytopenias. His cancer progressed and he succumbed to disease 10 months from initial diagnosis. Case 2: A 60 year old female presented with severe hypokalemia, metabolic alkalosis, hypercalcemia, cytopenias, HTN, weight loss, muscle weakness, nausea and mental status changes. CT abdomen showed bilateral adrenal hyperplasia. ACTH was 489 pg/ml, cortisol 81 ug/ml. MRI pituitary was unremarkable. PET-CT additionally showed hypermetabolic mediastinal lymph nodes and right upper lobe nodular opacity, and widespread osseous lesions. She was started on ketoconazole and antihypertensives. Bilateral adrenalectomy was considered but could not be performed due to rapid clinical deterioration. Etomidate was initiated. Fine needle aspiration of a mediastinal lymph node showed small cell carcinoma. Patient became too frail to receive systemic chemotherapy and succumbed within 2 weeks of hospitalization. Discussion: Most Ectopic ACTH Syndrome cases are caused by NET of the lung, pancreas and thymus. In children, Ewing’s sarcoma has been reported. Small cell carcinoma of lung, malignant pancreatic NETs, and medullary carcinoma of thyroid often present with metastasis and carry an ominous prognosis. Not all patients have clinical features of classic Cushing's syndrome. The outcome of EAS correlates with tumor type. Optimum treatment is surgical resection of the tumor, often not possible with metastatic disease. Hypercortisolism may be controlled with adrenal enzyme inhibitors and receptor blockers. Bilateral surgical adrenalectomy may be needed when symptoms are not controlled by medical management. Early and rapid control of Cushing’s Syndrome is important to facilitate antineoplastic treatment of the underlying tumor. Presentation: Friday, June 16, 2023