Immunohistochemical evaluation of a complex endocrinopathy

A patient with clinical and biochemical evidence of ectopic ACTH production is described. Autopsy revealed endocrine tumors of bronchus and pancreas with metastases to the liver, kidney, abdominal lymph nodes, and bone. Immunohistochemical methods established that the bronchial and pancreatic tumors were separate primary neoplasms each with its own hormone production; and allowed us to determine that the bronchial carcinoid was the source of ACTH and gave rise to the liver metastases, and that insulin was present in the cells of the pancreatic islet cell tumor. These methods also revealed a mild C-cell hyperplasia of the thyroid gland. We wish to stress the importance of the immunoperoxidase method in the evaluation of this and similar polyendocrine cases.