[Primary retroperitoneal seminoma--a rare germ cell neoplasm].

A 44-year old male presented himself with left-sided abdominal pain. On clinical examination a painless, enlarged supraclavicular lymph node on the left side and small atrophic testes were detected. Ultrasonography revealed a huge retroperitoneal mass. By biopsy of the retroperitoneal tumor the diagnosis of a seminoma was made, but neither in the orchidectomy specimen of the right side nor in the testicular biopsy of the left side a primary tumor or a scar could be identified. Thus, the diagnosis of a extragonadal primary retroperitoneal seminoma was made. The patient responded well to the combined chemotherapy consisting of cisplatin, bleomycin and etoposide. For distinction from an occult and/or burned-out seminoma testicular biopsy or surgical exploration of the testes with histology are mandatory.