Humoral antibodies against spermatopoietic cells associated with mediastinal germinoma.

A case of mediastinal germinoma in a 21-yr-old male is reported. The neoplasm exhibited a morphology similar to that of a testicular seminoma and was heavily infiltrated by lymphocytes and plasma cells. Germinal centres were also present in lymph follicles. Humoral antibodies (IgG), specific for spermatopoietic tissue, were present in the patient's serum. Antibody titres declined after surgical removal of the germinoma over a period of 2 yr, and antibody is no longer detectable at the present time. The implications of this observation are discussed with regard to defence mechanisms of the tumour host, and to the histogenesis of these rare neoplasms.