Somatostatin-receptor-negative carcinoid tumour responsible for Cushing's syndrome

A 30-year-old man presenting with Cushing's syndrome was admitted in 1995. A diagnosis of ectopically ACTH-secreting, primary-unknown abdominal carcinoid tumour was made. The patient's plasma ACTH and cortisol levels failed to decrease after short-term treatment with octreotide, and somatostatin-receptor scintigraphy did not show any accumulation in the tumour. The patient died 1 year after admission. This is a relatively rare somatostatin-receptor-negative case of this disease and it appears necessary to test for the presence of somatostatin receptors before treating with octreotide.