[Pathological study on thoracic carcinoids accompanied with Cushing's syndrome].

Eight patients with carcinoid tumors (5 from the lungs and 3 from the thymus) associated with Cushing's syndrome were studied. Among them, 5 were male and 3 female with a mean age of 32.5 years. Histologically, all were typical carcinoids. Immunohistochemically, tumor cells were strongly positive of NSE, chromogranin A and ACTH in all 8 cases. Some tumors also positive for S-100, calcitonin, HCG alpha and HCG beta. Various amounts of neurosecretory granules were found in the tumors by electron microscopy and ACTH positive dots were also noticed in some of the neurosecretory granules in the tumor cells by immunoelectron microscopical colloidal gold labelling technique. By in situ hybridization technique, overexpression of chromogranin A mRNA was detected in all of the tumors reported.