The role of electron microscopy in the diagnosis of unusual peripheral lung tumors.

The ultrastructure of the lung provides a cytomorphologic basis for the identification of unusual pulmonary neoplasms or unusual histologic variants of more common pulmonary lesions. Comparison of tumor cells with bronchioloalveolar lining cells and with pleural components has aided in the diagnosis of a spindle cell variant of a peripheral neuroendocrine cell tumor (carcinoid) and a tumor composed of cells resembling bronchioloalveolar epithelium (sclerosing hemangioma of lung).