Serum lactate dehydrogenase and its isoenzymes in men with maldescended testes.

Serum lactate dehydrogenase and lactate dehydrogenase isoenzymes were determined as a screen for testicular germ cell neoplasia in 130 men with maldescended testes. A testicular tumor was found on clinical examination in 1 patient, which was revealed to be embryonal carcinoma, teratoma, yolk sac tumor and carcinoma in situ on orchiectomy. Subclinical testicular germ cell neoplasia was found on testicular biopsy in 3 men (1 with microinvasive seminoma and 2 with carcinoma in situ). These 4 patients had normal serum lactate dehydrogenase and serum lactate dehydrogenase isoenzymes. Elevated serum lactate dehydrogenase was noted in 3 men without testicular germ cell neoplasia: 1 had predominantly increased serum lactate dehydrogenase isoenzymes 1 to 3 and 2 had slightly increased serum lactate dehydrogenase isoenzymes 3 and 4. Serum lactate dehydrogenase and lactate dehydrogenase isoenzymes were not sensitive to detect testicular germ cell tumors in a subclinical stage.