[Extra-gonadal germ-cell tumors]

Authors describe the clinico-pathological and immunohistochemical findings of two mediastinal (seminoma and yolk-sack) and a pineal mixed (seminoma and yolk-sack) tumours. In the mediastinal yolk-sack tumour the light microscopic picture of cellular components, alpha-fetoprotein (AFP), haemoglobin F (Hgb F), blood group antigen, carcinoembryonal antigen (CEA), post-digestion (neuraminidase) peanut antigen (neu-PNA) positivities suggest hepatic and intestinal differentiation. In some cells of mediastinal seminoma the glucose- and mannose-binding concanavalin-A (Con A) showed reaction. In the mixed tumour of the pineal region in addition to AFP positive cell cords some cell groups reacted with Leu-M1 (CD15) monoclonal antibodies raised against stage specific embryonic antigen 1 (SSEA1).