THU505 Severe Acute Hypercortisolism From Stable Pre-existing Lung Nodule

Disclosure: N. Raza: None. S. Wagle: None. R.N. Kiani: None. K. Kaput: None. A 63-year-old male with uncontrolled hypertension and Rheumatoid arthritis was admitted for acute psychosis, progressive asthenia, and severe refractory hypokalemia. He was afebrile on admission and blood pressure was 151/99 mmHg. Physical examination lacked typical Cushingoid appearance of moon facies, central obesity, or purple striae. Labs showed a potassium of 1.8 (ref: 3.3-5 mmol/L), HbA1c 6.0% (ref<=5.6 %), 24-hour urinary free cortisol of 9438 (ref<=60.0 ug/d) and random ACTH level of 229 (ref:7.7-63.3pg/ml). The presentation was felt to be consistent with ectopic ACTH dependent Cushing's syndrome. He was treated with ketoconazole 400 mg BID, Deep veinous thrombosis prophylaxis and trimethoprim-sulfamethoxazole daily for PJP prophylaxis. CT chest/abdomen/pelvis was performed and showed a 1.9 cm right middle lobe pulmonary nodule. Past records were reviewed and showed a stable lung nodule from 2020 (2.5 years earlier). Elective lung biopsy was discussed, and the patient was discharged home with plan for outpatient biopsy. Prior to his biopsy, he was readmitted with worsening agitation, hypertension, and extremity edema. After extensive discussion with CT surgery, a decision was made to perform robotic-assisted thoracoscopic resection of the right middle lobe with mediastinal lymph node dissection. Post-surgery his BP improved, agitation resolved, and cortisol level declined to 3.4 (ref: 6.0 - 18.4 ug/dL). Final pathology showed a well differentiated neuroendocrine tumor, low grade. Lymphovascular invasion was present, and one lymph node was positive for tumor. ACTH immunostaining was performed and was also positive. Ectopic ACTH dependent Cushing syndrome represents a rare condition, contributing to 5-20% of Cushing’s cases. Lung carcinoid tumor is one of the major causes of ectopic ACTH syndrome and typically resolves with surgery. Unusual in our case is the stability of the lung lesion prior to his acute decompensation and lymph node positivity. To date, we have not identified a reason for the indolent nature of his tumor. He is currently on a hydrocortisone taper and is actively undergoing treatment planning with our multidisciplinary peer review process. Essential to his management is the coordination of multiple providers, which includes complex medical decision making and treatment decisions. In the future, lung carcinoid should be considered in the differential for persons with difficult to control hypertension and a stable pulmonary nodule Presentation: Thursday, June 15, 2023