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Cancer is a disease in which cells grow in an abnormal way. Normally, the cells divide in a controlled manner. If cells keep dividing when new cells are not needed, a mass of tissue called a tumor forms.

A tumor can be benign or malignant. A benign tumor is not cancer and will not spread to other parts of the body. A malignant tumor is cancer. Cancer cells invade and damage tissue around them. They can also enter the lymph and blood streams, spreading to other parts of the body. Testicular cancer is the development of malignant cells in the one or more of the testicles.

Normal Anatomy and the Development of Testicular Cancer

The testicles (or testes) are a pair of male sex glands that produce sperm and male hormones. They are located under the penis in a sac-like pouch called the scrotum. At the top of each testis is a bunch of tiny tubules that collect and store sperm. This structure is called the epididymis. The sperm travel from the epididymis through the vas deferens and out through the urethra during ejaculation.

External Male Reproductive System

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Cell division and cell death are a normal process in the body to replace old or damaged cells. Cancerous cell growth may related to changing hormone levels or chromosomal abnormalities in the sperm-producing (germ) cells of the testicles.

Though rare, testicular cancer is the most common form of cancer in young men between the ages 20 and 35 years. According to the National Cancer Institute, an estimated 8,430 American men will be diagnosed with testicular cancer in 2015, resulting in an estimated 380 deaths.

Currently, over 95% of testicular cancers are cured.


SEER stat fact sheets: Testis cancer. National Cancer Institute website. Available at: Accessed September 8, 2016.

Testicular cancer. American Cancer Society website. Available at: Accessed September 8, 2016.

Testicular cancer. EBSCO DynaMed Plus website. Available at: Updated January 12, 2016. Accessed October 5, 2016.

Testicular cancer. Merck Manual Professional Version. Available at: Updated November 2013. Accessed September 8, 2016.

Last reviewed September 2016 by Mohei Abouzied, MD  Last Updated: 9/17/2014

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