ACTH-producing pancreatic neuroendocrine tumours are rare, with limited data about effective antitumor therapies.<h4>Case report</h4>A 58-year-old man with a history of type-2 diabetes mellitus and arterial hypertension was diagnosed with Cushing's syndrome (CS) secondary to an ACTH ectopic production from a well-differentiated neuroendocrine tumour of the pancreas metastatic to the liver. The gene discussed is POMC; the disease is diabetes mellitus.