LBODP064 A Rare Case Of Paraneoplastic Cushing Syndrome Associated With Pulmonary Carcinoid Tumor

A 67-year-old female with a history of primary pulmonary carcinoid tumor with metastasis to the liver presented with shortness of breath and generalized weakness. On presentation, her vital signs were BP 170/100 mm Hg, pulse 99/min, RR 18/min, O2 saturation 85% on room air. Physical exam was significant for diffuse rhonchi in bilateral lungs. Initial labs showed marked hypokalemia with K+ 2.5 and HCO3- 42. CT scans showed increased numbers of nodules and sizes in the lungs and numerous large liver masses. The adrenal glands and aldosterone-to-renin ratio were within normal limits. A random cortisol level was 113.14 ug/dL (2.50-12.50) with a concomitant elevated ACTH level of 353.6 pg/mL (7.2-63.3), while brain MRI was negative for pituitary or metastatic lesion. A liver mass biopsy revealed a transformation into a high-grade neuroendocrine tumor with a Ki-67 of 32%. A low dose dexamethasone suppression test showed a cortisol level of 66. 08. Interpreting this result and the imaging studies, it was determined that hypercortisolism was secondary to ectopic ACTH production. This clinical presentation and findings supported her cancer transformation to a functional metastatic neuroendocrine cancer with a paraneoplastic syndrome previously unknown. She was started on spironolactone as a potassium-sparing diuretic, itraconazole to inhibit cortisol synthesis based on inpatient formulary at that time, and combination chemotherapy with cisplatin and etoposide. Over the next few weeks, she developed signs of Cushing syndrome with leg swelling, facial puffiness, proximal muscle weakness, muscle loss, easy bruising, abdominal striae, coccydynia, glucose intolerance, and acid reflux. She had complications of peptic ulcer disease with bleeding, Clostridium difficile colitis, bacterial pneumonia, persistent hypokalemia, hypomagnesemia, and chemotherapy-induced anemia and severe thrombocytopenia. A repeat cortisol level was >150. 00 ug/dL despite the uptritation of itraconazole, suggesting not so much success. With insurance approval, she was started on ketoconazole, on which the cortisol levels on Days 5, 12, and 19 were 114.74 ug/dL, 126.84 ug/dL, and 118.42 ug/dL, respectively. Given uncontrolled hypercortisolism, a novel cortisol synthesis inhibitor, osilodrostat, was ordered and approved. However, two days later, the patient required another hospitalization for respiratory failure and severe sepsis from Coronavirus Disease 2019 pneumonia and Acinetobacter radioresistens bacteremia, and she passed away. This case highlights the therapeutic challenge of managing a late presentation of Cushing syndrome from ectopic ACTH production secondary to the progression of metastatic lung cancer. As such, clinicians should periodically consider screening for the subclinical-Cushing syndrome to diagnose such cases early, preventing such consequences of overt Cushing syndrome. Presentation: No date and time listed