ACTH-Producing Neuroendocrine Carcinoma of the Liver with Cushing's Syndrome

Paraneoplastic Cushing's syndrome arises when neuroendocrine tumors cause excess glucocorticoid production. We report a case of ectopic ACTH-producing liver neuroendocrine tumor. A 71 y.o. female with a history of rectal squamous carcinoma presented with fatigue and diffuse swelling. Liver biopsy revealed metastatic neuroendocrine carcinoma. Workup revealed markedly elevated morning cortisol and ACTH. Overnight dexamethasone suppression testing and positive immunostaining for ACTH on biopsy suggested paraneoplastic Cushing's syndrome secondary to neuroendocrine hepatic tumors with bony metastasis. This explained the patient's persistent anasarca, hyperglycemia, and electrolyte abnormalities. Despite multiple interventions, the patient's clinical status declined, and she expired.