How is choriocarcinoma?

➢ Tumor in which the pluripotential neoplastic germ cells differentiate into cells resembling placental trophoblasts ➢ Primary tumors often are small and nonpalpable, even in patients with extensive metastatic disease ➢ Composed of sheets of small cuboidal cytotrophoblast like cells that are irregularly intermingled with or capped by large, eosinophilic syncytiotrophoblast like cells containing multiple dark, pleomorphic nuclei ➢ HCG can be identified in the syncytiotrophoblastic cells by immunohistochemical staining