Incidence and distribution of carcinoma in situ in testes removed for germ cell tumour: possible inadequacy of random testicular biopsy in detecting the condition.

A total of 127 testicular specimens with germ cell tumours were stained immunohistologically for placental alkaline phosphatase to investigate the presence and topographic distribution of carcinoma in situ cells adjacent to the invasive tumours. Carcinoma in situ was detected in 72% of the cases. In 60% of the cases positive for placental alkaline phosphatase the distribution of carcinoma in situ was not diffuse, as claimed in the literature, but focal. Clinicians screening for carcinoma in situ by only one random biopsy have, therefore, to be aware of possible false negative results.