What is the most common histological type of testicular cancer?

Seminoma is the most common histological type of testicular cancer, accounting for approximately 50% of all cases. It typically occurs in younger men, particularly in the age range of 15 to 35 years. Histologically, seminomas are characterized by bulky, homogeneous testicular masses that have a well-defined capsule and consist of sheets of large, ovoid germ cells with clear cytoplasm. These tumors are often associated with a good prognosis, especially when detected early, and they are generally responsive to radiotherapy.

The other types of testicular tumors mentioned, such as embryonal carcinoma, teratoma, and choriocarcinoma, are less common and have different histological features and clinical behaviors. For instance, embryonal carcinoma tends to present at a younger age than seminoma but is more aggressive. Teratomas can occur at various ages and have mixed types of tissues, while choriocarcinoma is rare and often associated with higher levels of human chorionic gonadotropin (hCG). The relative rarity of these cancers compared to seminoma underscores why seminoma is identified as the most prevalent histological type of testicular cancer.