Alternating Therapy With Osilodrostat and Etomidate in Severe Ectopic Cushing’s Syndrome Complicated by Silent Bowel Perforation

Ectopic adrenocorticotropic hormone (ACTH)‐dependent Cushing’s syndrome (CS), ectopic ACTH secretion (EAS) is a rare condition caused by ACTH‐secreting neuroendocrine tumors (NETs), such as bronchial carcinoids. We report a 65‐year‐old woman with severe EAS complicated by bowel perforation. She presented with hypokalemia (K + 2.3 mmol/L), metabolic alkalosis, resistant hypertension (180/110 mmHg), worsening diabetes (HbA1c 6.7%–9.1%), proximal muscle weakness, and 14 kg weight gain over 3 months. A silent sigmoid colon perforation required emergency resection and colostomy. Biochemical tests confirmed hypercortisolism (urine free cortisol UFC, 1256 µg/24 h, plasma ACTH 175 pg/mL, and cortisol >40 µg/dL post‐dexamethasone). Imaging identified a 2.3 cm pulmonary nodule with mild uptake on Ga‐68 DOTATATE PET/CT. Bronchoscopic biopsy confirmed an ACTH‐positive low‐grade bronchial carcinoid tumor. Initial treatment with osilodrostat was interrupted due to acute illness and oral medication intolerance. Intravenous etomidate was employed in the ICU for rapid cortisol suppression, followed by resumption of osilodrostat after stabilization. Thoracoscopic lobectomy confirmed a low‐grade carcinoid tumor (Ki‐67 < 2%). Postoperatively, cortisol normalized, electrolytes stabilized, and HbA1c improved to 6.5%. This case highlights bowel perforation as a severe complication of EAS and underscores the importance of dynamic, alternating therapy with osilodrostat and etomidate, along with individualized surgical and medical management strategies.