Ectopic adrenocorticotropic hormone syndrome in a case of duodenal neuroendocrine tumor presenting with liver metastasis

Ectopic adrenocorticotropic hormone (ACTH) syndrome is an uncommon disorder and comprises about 15% of all patients with Cushing's syndrome (CS). Duodenal carcinoids are rare, indolent tumors usually associated with a benign progression. We hereby report a rare case of CS resulting from ectopic ACTH secretion from a duodenal neuroendocrine tumor (NET) presenting with liver metastasis. A 37-year-old female presented with abdominal discomfort and dyspepsia of 1-month duration. Ultrasound abdomen suggested a well-defined hypoechoic lesion in the left lobe of the liver, suggestive of neoplasia. On clinical examination, she had Cushingoid features and persistent hypokalemia. Midnight ACTH and cortisol levels were grossly elevated at 1027 pg/ml (n < 46 pg/ml) and 87.56 μg/dl (n < 7.5 μg/ml), respectively. Both overnight and high-dose dexamethasone suppression test confirmed nonsuppressed cortisol levels - 86.04 and 84.42 μg/dl (n < 1.8 μg/ml), respectively. Magnetic resonance imaging brain showed a structurally normal pituitary gland. Computed tomography scan of the abdomen revealed hepatic lesion with bilateral adrenal enlargement. A diagnosis of ectopic ACTH-dependent CS was made. Intraoperatively, a duodenal lesion of 0.5 cm × 0.5 cm was identified alongside an 8 cm × 6 cm exophytic lesion in segment IV of the liver. Frozen section of the duodenal lesion was positive for NET. She underwent a Whipple's surgery, cholecystectomy, and left hepatic lobectomy. Postoperatively, she showed clinical and biochemical remission. Herewith, we report the third case of duodenal carcinoid tumor presenting as ectopic ACTH syndrome and the first with liver metastasis.