Occult ectopic ACTH syndrome

Abstract

A 38-year-old male was diagnosed with Cushing's syndrome. Biochemical tests showed hypokalaemia and hypercortisolaemia, with failure of suppression following high dose dexamethasone, suggesting an ectopic or adrenal source. Adrenocorticotrophic hormone levels were >100 IU/L (normal 3–14 IU/L). Pituitary magnetic resonance imaging was normal as was the chest radiograph, spiral computed tomography and bronchoscopy. Adrenal imaging revealed hyperplastic glands with no adenoma. In-octreotide scan was performed, demonstrating a focal area of increased tracer uptake in the left hemithorax close to the midline (figure). The patient was treated with metyrapone and underwent bilateral adrenalectomy but died postoperatively. Post-mortem examination demonstrated a normal pituitary and bilaterally hyperplastic adrenal glands with a bronchial carcinoid in the left hilar region corresponding to the site of increased tracer uptake. In-octreotide scanning may have a useful role in occult ectopic ACTH syndrome.