ABSTRACT
The incidence of testicular tumors in man is considerably different from that in nonhuman species. Testicular tumors in man are rare relative to testicular tumors in rodents. Furthermore, the type of testicular tumor in men is most frequently of germ cell or Sertoli cell origin. In rats (and some strains of mice), the cell type of the gonadal tumor is most often the Leydig cell. Leydig cell tumors in rats are quite restrictive and are found more frequently in the Fischer (35) and the Wistar strains (74).
