A Case of Ectopic ACTH-Producing Pulmonary Carcinoid Arising in an Extralobar Pulmonary Sequestration

Ectopic adrenocorticotrophic hormone (ACTH)-producing bronchopulmonary carcinoid arising in a bronchopulmonary sequestration is extremely rare. The case of a 67-year-old woman with a 1.7-cm nodule in the mediastinal side of the left lower lobe is presented. At 52 years of age, she was diagnosed as having ACTH-dependent Cushing's syndrome (CS). However, no ectopic source of ACTH-secretion was detected. Seven years later, she underwent a bilateral adrenalectomy because of aggravation of her health condition. This time, tumor excision was performed by thoracoscopic surgery. The tumor adhered sparsely to the mediastinal pleura and the left lower lobe and was bluntly separated from these tissues. Pathologically, the tumor was a typical carcinoid arising in an extralobar pulmonary sequestration. Immunohistochemical staining confirmed the secretion of ACTH by bronchopulmonary carcinoid tumor cells. After surgery, the serum ACTH level was almost normalized, and the dexamethasone (1 mg) suppression test showed significant suppression of ACTH.