Polypoid pulmonary endodermal tumor resembling fetal lung: report of a case.

Pulmonary blastoma is a rare malignant neoplasm that histologically resembles airway structures and mesenchymal supporting tissues seen in the early phases of fetal lung development. The tumor either is biphasic with immature epithelial and stromal components or consists solely of an epithelial component. The preferred terminology for the latter is pulmonary endodermal tumor resembling fetal lung. Pulmonary blastoma is usually peripheral in location, and rarely does this tumor present intrabronchially. We report a case of pulmonary endodermal tumor resembling fetal lung presenting as a polypoid intrabronchial mass.