Seminoma is a type of testicular cancer that originates from germ cells, which are responsible for producing sperm. It is usually slow-growing and typically affects younger men, particularly those between the ages of 15 and 35. Seminomas are generally classified into two types: classic seminomas and spermatocytic seminomas, with classic seminomas being more common. Treatment often involves surgery, radiation, and chemotherapy, depending on the stage of the disease.