Alveolar Cell Carcinoma

A multinodular alveolar cell carcinoma with extrapulmonic metastases was examined by electron microscopy. The tumor cell lining the alveolar epithelial basement membrane had ultrastructural features consistent with carcinoma and also resembled type B alveolar cells. It was concluded that the tumor cell in this alveolar cell carcinoma was derived from the type B alveolar epithelial cell.