Immunohistochemical diagnosis of preinvasive germ cell cancer of the testis.

The aim of the study was to identify testicular carcinoma in situ (CIS), a precursor of germ cell tumours (GCT), in patients from the high risk groups, using classic and alternative immunohistochemical methods. 70 patients with 46,XY karyotype were examined. Whole gonads or biopsy specimens were fixed in Bouin's fluid. In cases with dysgenetic male pseudohermaphroditism (DMP), gross histopathology revealed sex cord tumour gonadoblastoma in 4 and malignant dysgerminoma in 1 out of 23 patients. In all patients, paraffin sections were treated with antibodies against placental-like alkaline phosphatase (PLAP), a classic immunohistochemical marker of GCT and CIS. CIS was detected immunohistochemically in 10 out of 23 cases with DMP (43.5%), in 1 out of 10 cases with androgen insensitivity syndrome (10%), in 3 out of 18 cases operated previously because of already developed GCT in contralateral testis (16.6%) and in 1 out of 3 patients with cryptorchidism in anamnesis (33.3%). CIS was not found in 16 examined adult infertile men with azoospermia. In addition to PLAP investigation, 12 cases with DMP and 6 cases with GCT were examined using M2A and TRA-1-60 antibodies, the alternative immunohistochemical markers of CIS. While in DMP positive reactions for M2A and TRA-1-60 accompanied PLAP reaction in 1/3 of cases, M2A accompanied PLAP in all cases with GCT. The positive reaction for TRA-1-60 accompanied PLAP and M2A in 1 case with GCT. The results indicate that among different risk groups the highest incidence of CIS occurs in DMP. Screening for CIS is of importance also in cryptorchidism, androgen insensitivity syndrome and in men who underwent gonadectomy because of unilateral GCT. The immunostaining for PLAP seems to be more discriminative procedure. The positive staining of CIS cells with M2A and TRA-1-60 antibodies may be indicative for more advanced neoplastic transformation.