Pulmonary blastoma: an ultrastructural study emphasizing intestinal differentiation in lung tumors

Features of intestinal differentiation, including the presence of brush borders, have been described previously in a pulmonary blastoma following xenotransplantation in athymic nude mice. This paper reports similar findings in a pulmonary blastoma subjected directly to electron microscopic study. Ultrastructural manifestations of intestinal differentiation in other types of primary lung tumors are also discussed.