Embryonal CA : Solid pattern vs Seminoma
Solid pattern of embryonal carcinoma may mimic seminoma. Seminoma usually have less cytologic atypia and more distinct cytoplasmic borders. In addition, seminomas are negative for CD30; negative or only focally positive for cytokeratin; and positive for CD117. Embryonal carcinoma usually have reverse immunohistochemical profile (CD30+, cytokeratin +, CD117 neg).