SUN-385 A Rare Case of Ectopic ACTH Secretion by Pancreatic Adenocarcinoma

Background Ectopic ACTH secretion caused by pancreatic neuroendocrine tumor is rare, but is responsible for 15% of ectopic Cushing syndrome. Their presentation and treatment are challenging because their preoperatory diagnosis and treatment are difficult due to its divergent and heterogeneous nature. CaseThe patient is a 65year old male with recent diagnosis of pancreatic cancer with liver metastases opting for naturopathic treatment, history of excessive alcohol use, gout, and biliary stent placement, presented to the ED with abnormal labs. On admission he was noted to be bradycardic with heart rate in 50s, WBC slightly elevated at 12.3, potassium 1.6, bicarbonate 50, calcium 6.5, bilirubin 8.8, ALT 79, AST 63, TSH undetectable, and T3-T4 extremely low. Patient also had lower extremity edema, lethargy, and confusion. Initial presentation was concerning for myxedema coma. Ultrasound for DVT was negative.Twelve-lead EKG demonstrated a ventricular rate of 58, sinus bradycardia with second degree AV block . IV Synthroid and replacement protocol was initiated. MRI of the brain was unremarkable. Patient noted to have upper extremity contractures. 24 hour urine free cortisol was 12,000 (normal 7.2-60 pg/mL ); ACTH 719 pg/mL (normal 4.5 - 20 pmol/L); CEA 10.3 (normal <3 ng/mL, CA19-9 762.0 (normal <40 U/mL). Continued hypokalemia as well as tetany and hypocalcemia secondary to metabolic alkalosis over the next few days were largely due to multifactorial reasons, including Keto-alkalione diet, profound weight loss, chronic stooling and recent development of ectopic Cushing’s with mineralocorticoid excess and hyperaldosteronism resulting in increased tubular wasting of potassium. Patient was continued on PO + IV repletion. Hydrocortisone and Synthroid were discontinued. Patient was started on amiloride PO and clindamycin and Bactrim due to intrinsic immunosuppression. No Ketoconazol was given because of transaminitis. The patient and his family opted for hospice care as he was not a candidate for oral chemotherapy or bilateral adrenalectomy for elevated cortisol levels and for his prognosis of <2 months. Conclusion; Exocrine pancreatic tumors are the most common type of pancreatic neoplasm and commonly consist of purely exocrine characteristics. The significance of this case lies in the extreme rarity of pancreatic adenocarcinoma exhibiting endocrine traits with only one previous case in the literature. This case suggests that exocrine pancreatic cancer with endocrine features is a distinct condition and that certain guidelines and protocols may be necessary for this entity. Resources 1. Gullo, L., et al. “Pancreatic Exocrine Carcinoma Producing Adrenocorticotropic Hormone.” Pancreas, vol. 7, no. 2, 1992, pp. 172-176., doi:10.1097/00006676-199203000-00007.