Cushing's syndrome secondary to bronchopulmonary carcinoid tumor: report of two cases and literature review

Abstract

Bronchopulmonary carcinoid tumors have been associated with a variety of endocrine disorders including Cushing's syndrome (CS), which is caused by ectopic adrenocorticotrophic hormone (ACTH) secretion. We report two cases of CS secondary to bronchopulmonary carcinoid tumors. The first patient, a 29-year-old woman, presented hypokalemia, high serum ACTH level and high free-urinary cortisol, raising suspicion of an ectopic ACTH syndrome. Chest computed tomography and Octreoscan showed a peripheral nodule in the left-superior lobe of the lung. After lobectomy, a typical bronchopulmonary carcinoid was diagnosed. The second patient, a 16-year-old boy, presented "moon face" and progressive asthenia, high serum ACTH level and high free-urinary cortisol, raising the same hypothesis. Chest computed tomography and Octreoscan showed a peripheral nodule in the middle lobe. After lobectomy, an atypical bronchopulmonary carcinoid was diagnosed. Both cases had IA stage (T1N0M0), positively immunostaining for chromogranin and ACTH. Neither of these patients had hypophysary microadenomas, adrenal adenomas or recurrence of CS after surgical treatment, demonstrating that CS was caused solely by the presence of the bronchopulmonary carcinoid tumors.