Definition of Testicular cancer:

Testicular cancer is cancer that starts in the testicles, the male reproductive glands located in the scrotum.

Causes, incidence, and risk factors:

The exact cause of testicular cancer is unknown. There is no link between vasectomy and testicular cancer. Factors that may increase a man's risk for testicular cancer include:

• Abnormal testicle development
• History of testicular cancer
• History of undescended testicle
• Klinefelter syndrome

Other possible causes include exposure to certain chemicals and HIV infection. A family history of testicular cancer may also increase risk.

Testicular cancer is the most common form of cancer in men between the ages of 15 and 35. It can occur in older men, and rarely, in younger boys.

White men are more likely than African-American and Asian-American men to develop this type of cancer.

There are two main types of testicular cancer: seminomas and nonseminomas. These cancers grow from germ cells, the cells that make sperm.

Seminoma: This is a slow-growing form of testicular cancer usually found in men in their 30s and 40s. The cancer is usually just in the testes, but it can spread to the lymph nodes. Seminomas are very sensitive to radiation therapy.

Nonseminoma: This more common type of testicular cancer tends to grow more quickly than seminomas. Nonseminoma tumors are often made up of more than one type of cell, and are identified according to these different cell types:

• Choriocarcinoma (rare)
• Embryonal carcinoma
• Teratoma
• Yolk sac tumor

A stromal tumor is a rare type of testicular tumor. They are usually not cancerous. The two main types of stromal tumors are Leydig cell tumors and Sertoli cell tumors. Stromal tumors usually occur during childhood.