The prepubertal testis (prenatal and postnatal): its relationship to intratubular germ cell neoplasia: a combined Pediatric Oncology Group and Children's Cancer Study Group.

Seminiferous tubules adjacent to germ cell tumors (GCT) in prepubertal boys frequently contain increased germ cells with abundant, clear cytoplasm. These cells are placental alkaline phosphatase (PLAP) negative and are usually not considered to represent intratubular germ cell neoplasia (ITGCN). A recent case report found p53 and proliferating cell nuclear antigen (PCNA) positivity in such cells and equated these PLAP-negative cells with ITGCN. Because the proto-oncogene c-kit is also a marker of ITGCN, immunohistochemical tests for c-kit and PLAP were performed on 28 testes adjacent to prepubertal GCT in children aged 2 to 45 months. Additional slides from testes not associated with GCT from 18 preterm infants and children ages 19 weeks to 7 years were also tested. An adult testis with seminoma and ITGCN served as a positive control. PCNA, PLAP, and p53 were tested on available slides. No intratubular germ cells adjacent to GCT in prepubertal children were positive for PLAP or c-kit; five of seven were positive for PCNA; p53 was present in the two examined. These results indicate that germ cells adjacent to infantile GCT are proliferative but not neoplastic and offer additional evidence that intratubular germ cells and GCT in prepubertal boys are different from those of adolescents and adults.