Asymptomatic pulmonary granular cell tumor presenting as a coin lesion.

Granular cell tumor is a rare, usually benign neoplasm of neurogenic origin first described in 1926. Only 46 lesions, including the present case, of the 500 reported cases of this tumor, originated within the tracheobronchial tree. The case reported here is distinctly unusual because of its asymptomatic presentation as a coin lesion on chest roentgenogram. Electron microscopic examination of the tumor is presented.