Malignant biphasic tumors of the lungs.

Malignant biphasic tumors of the lungs are rare primary tumors of the bronchopulmonary system. These tumors are composed of malignant epithelial and mesenchymal elements and together comprise <2% of all primary pulmonary neoplasms. The tumors belonging to this group include pulmonary blastoma, pleuropulmonary blastoma, and carcinosarcoma. In this study, the clinicopathologic features, immunohistochemical phenotype, molecular biological characteristics, and the differential diagnosis of these uncommon neoplasms are discussed.