Testicular cancer. Coloured transmission electron micrograph (TEM) of a dividing seminoma cancer cell in tissue from a testis (testicle). Seminomas are malignant (cancerous) tumours that tend to spread to lymph nodes via the lymphatic and is one of the most treatable and curable cancers, with a survival rate above 95% if discovered in early stages. Magnification: x1500 when printed at 10 centimetres wide.system. They are the most common form of testicular cancer and occur most often in men between the age of 30 to 45 years. It is a malignant neoplasm and is one of the most treatable and curable cancers, with a survival rate above 95% if discovered in early stages. Human tissue. Magnification: x1500 when printed at 10 centimetres wide.