Immuohistochemical study in lesions referred to as “blastoma” in various organs

The immunohistochemical staining patterns of nephroblastoma, hepatoblastoma and pulmonary blastoma with special reference to mixed mesodermal tumors of genital tract were studied for markers of epithelial and mesenchymal differentiation to clarify their phenotypic nature and, possibly, their histogenesis. The pulmonary blastoma resembled adult mixed mesodermal tumor both in the morphological and immunohistochemical characteristics, demonstrating that pulmonary blastomas are mixed tumors with origin from a primitive pluripotential mesenchymal cell. In nephroblastoma the blastemal cells showed S-100 immunoreactivity. The 78-year-old female with hepatocellular carcinomal transformed into hepatoblastoma suggested the possibility that a tumor with endodermal origin would show dedifferentiation or metaplasia to a mesenchymal tissue.