An ectopic, ACTH producing, oncocytic carcinoid tumor of the thymus: report of a case.

A 39-year-old man with an ACTH producing oncocytic carcinoid of the thymus is reported here. His symptoms were pigmentation, facial and pretibial edema, and high blood pressure. Endocrinological examination revealed the ectopic ACTH syndrome and, especially, high content in the intrathoracic venous blood. On histological examination, the tumor was found to be composed of uniform eosinophilic cells, with no argentaffin granules being demonstrated. Ultrastructural findings revealed a large number of mitochondria and numerous distinct electron-dense neurosecretory granules in the cytoplasm. Abnormally high levels of ACTH, beta-endorphin and gamma-MSH were also found in this tumor tissue. By total extirpation of the tumor, clinical symptoms and laboratory data were entirely normalized.