[Immunoperoxidase study of 80 germ cell tumours of the testis in adults (author's transl)].

Twenty-six tumours of the seminoma type and 54 embryonic carcinomas of the testis were studied with immunoperoxidase, using an anti-beta HCG immune serum and an anti-alpha FP immune serum. The results obtained in first group suggest the possibility of a new type of "pseudo-seminoma" tumours, with high levels of circulating HCG probably due to proliferation of trophoblasts. In the second group, 88% of the tumours gave positive response to one or the other immune sera. However, the anti-alpha FP-positive structures were similar to those of pure vitelline tumours, and the anti-beta HCG-positive structures were syncytiotrophoblastic elements different from those of conventional carcinomas. The combined results of histology, immunohistochemistry and pre-operative biological tests should lead to improved identification of malignant germ cell tumours of the testis.