Oncocytic carcinoid of the lung.

A 49-year-old male was hospitalized after chest roentgenogram revealed a coin lesion in the right of middle lung field. Right upper lobectomy with lymphadenectomy was performed. The diagnosis on pathological examination was of carcinoid tumor. However, electron-microscopic examination revealed hyperplasia of numerous mitochondria and neurosecretory granules in the cytoplasm of the tumor cell, thus the diagnosis of oncocytic carcinoid was made. The patient has been well and experienced neither recurrences nor relapse 2 years after the surgery.