2021 Volume 35 Issue 6 Pages 736-741
In 200X, we diagnosed a man in his 70s with Cushing syndrome, due to ectopic adrenocorticotropic hormone (ACTH) secretion. Abdominal computed tomography (CT) revealed a duodenal lesion that was suspected to be ATCH-producing based on adrenal venous sampling. He underwent a pancreatoduodenectomy; however, the lesion was histopathologically diagnosed as an inflammatory nodule. While the cause of ectopic ACTH production remained unknown, an adrenocortical steroid synthesis inhibitor was prescribed to control the adrenal cortical function.
Twelve years later, chest CT showed a 20-mm nodule in the lower lobe of his left lung. A thoracoscopic left lower lobe wedge resection was performed, and postoperative histological diagnosis revealed that it was an ACTH-producing typical carcinoid tumor. After the operation, he presented with hypoadrenocorticism with elevated ACTH levels, likely due to the long-term use of adrenocortical steroid synthesis inhibitors. Supplemental steroids normalized his serum ACTH levels. Neither the carcinoid tumor nor Cushing syndrome showed any signs of recurrence five years after the tumor was resected. This patient's ACTH-producing lesion was identified > 10 years after a diagnosis of ectopic ACTH syndrome was made, he was placed on steroid synthesis inhibitors and this resulted in adrenal insufficiency after the carcinoid tumor was resected. The treatment of ectopic ACTH syndrome primarily involves removal of the ACTH-producing lesion. Radiological workup, including somatostatin receptor scintigraphy, is essential for lesion detection. In particular, thoracic evaluation should be emphasized because carcinoid tumors and small cell carcinomas of the lung are the causes of approximately 50% of cases of ectopic ACTH production.
