The nucleus (N) shows irregular indentations and the heterochromatin is dispersed in central and peripheral clumps. Stubby microvilli project from the apices of the cell as well as the lateral aspect and base. Cytoplasmic organelles consist of mitochondria, rough endoplasmic reticulum and numerous polyribosomes. Electron dense granules (arrowhead) and lamellar myelin figures are surfactant granules in the cytoplasm of the neoplastic Type II pneumocyte.