Histologic characterization of gonadal stromal tumors induced by intrasplenic autografting of testicular tissue.

Intrasplenic heterotransplantation of infantile testis is a conventional method to produce testicular tumors in adult castrated rodents. To avoid possible immunological interferences in the tumorigenic process in the allografted testis, the testicular tissues were autografted into the spleen of 88 castrated Wistar strain rats. Intrasplenic tumors developed in 64 animals (73% incidence) during an experimental period of 24 months, and 91% of these were histologically categorized as gonadal stromal tumors including Sertoli cell tumors, Leydig cell tumors, mixed forms of these and granulosa cell tumors. Although radioimmunoassay revealed elevated levels of serum sex-steroid hormones in 19 tumor-bearing rats, the levels of the serum gonadotropins were not increased. The results indicate that the intrasplenic testicular cells can develop into both Sertoli and granulosa type tumors. Intrasplenic autografting is a feasible and reproducible method to induce testicular gonadal stromal tumors with a high incidence, and thus deserves further attention.