The tumor replaces most of the testis proper except for a thin peripheral rim. The tumor has a lobulated cut surface and is rather homogenous and fleshy.
Seminomas are germ cell neoplasms.
Peak incidence in the fourth decade of life. On cut section, the tumor is usually gray-white, homogenous and lobular. Necrosis and hemorrhage are inconspicuous in small tumors and more notable in larger tumors. Typical seminoma is composed of monotonous sheets of uniform round cells with rather clear cytoplasm and centrally located round nuclei with prominent nucleoli. Seminoma occur most frequently in the fourth and fifth decade of life.