Pleomorphic adenoma in the periphery of the lung. Report of a case and review of the literature.

A pleomorphic adenoma of the lung recurred after 9 years. The primary tumor consisted mainly of cartilaginous and fibrous elements with a small area of epithelial cell nests, whereas the second one possessed epithelial cell nests with cartilaginous stroma. Immunohistochemical studies showed that both tumors had neoplastic cells with immunoreactive S100, keratin, actin, vimentin, and glial fibrillary acid protein-positive cytoplasm. The primary tumor, which was resected from the periphery of the lung, was not connected with the trachea or the bronchus macroscopically. To our knowledge, the literature contains only six reports of pleomorphic adenoma in the lung.