Ectopic Cushing's syndrome. A metastatic hepatic neuroendocrine tumour: case report and literature review.

This report describes a rare instance of an adrenocorticotropic hormone (ACTH)-secreting metastatic hepatic neuroendocrine tumour (MHNET) exhibiting as an ectopic Cushing's syndrome. A 41-year-old woman with a history of supraglottic neuroendocrine tumour presented with rapid weight gain, severe hypokalemia, and hypercortisolism. Pituitary imaging was unremarkable. However, the DOTATATE PET/CT showed a large liver lesion. Initiating etomidate infusion caused a rapid drop in cortisol, leading to severe vasoplegic and septic shock, which delayed the surgery. The patient required intensive care stabilization pre-operatively and treatment with osilodrostat, which was then followed by surgical management: left lateral hepatectomy and gastric wedge resection. ACTH levels markedly decreased postoperatively, reflecting successful management. This emphasizes that careful medical management and multidisciplinary collaboration are essential in treating severe, potentially life-threatening ectopic hypercortisolism.