Overview
What the Disease Is
Most testicular cancers are germ cell tumours derived from embryonic primordial germ cells.
Most testicular cancers are germ-cell tumours derived from embryonic primordial germ cells. The two broad groups are seminoma and non-seminoma. Seminoma is made up of relatively uniform cells resembling primordial germ cells. Non-seminomatous germ-cell tumours may contain embryonal carcinoma, yolk-sac tumour, choriocarcinoma, teratoma, or mixed elements. This distinction matters because marker patterns, growth behaviour, treatment response, and surveillance choices differ. Testicular cancer is most often identified in adolescents and young adults, commonly as a firm, painless change in one testis. An undescended testis increases risk even after orchiopexy; a personal or family history of testicular cancer also raises concern. A painless mass is not automatically cancer, but an intratesticular mass should be treated as malignant until appropriate assessment proves otherwise.