While hCG concentration may be inceased in patients with either nonseminoma or seminoma histology, the AFP concentration is increased only in patietns with nonseminoma." - Harrison Seminomas represent about 50% of all Germ cell tumors of testis. Median age is 4th decade (Nonseminomas are most frequent in the 3rd decade). Seminomas follow a more indolent course. Most seminomas (70%) present with stage I disease (disease limited to testis), about 20% with stage II disease (with retroperitoneal metastases), and 10% with stage III disease (spread beyond retroperitoneum) Seminomas as well as non-seminomas typically metastasize through lymphatics (except Choriocarcinoma which demonstrates early hematogenous spread) Seminomas are one of the most radiosensitive tumors (Non seminomas are insensitive to radiation). ref : Bailey & Love 25/e p1384