Testicular Cancer

Testicular cancer begins when healthy cells in a testicle change and grow uncontrollably, forming a mass called a tumor. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body.

About the testicles

The testicles are part of a man’s reproductive system. Each man has two testicles, and they are located under the penis in a sac-like pouch called the scrotum. They can also be called testes or gonads. The testicles produce sperm and testosterone. Testosterone is a hormone that plays a role in the development of a man’s reproductive organs and other characteristics.

About testicular cancer

Most types of testicular cancer develop in the sperm-producing cells known as germ cells, and are referred to as germ cell tumors. Germ cell tumors in men can start in several parts of the body:

  • The testicles, which is the most common location

  • The back of the abdomen near the spine, called the retroperitoneum

  • The central portion of the chest between the lungs, called the mediastinum

  • The lower spine

  • Very rarely, a small gland in the brain called the pineal gland

Testicular cancer is almost always curable if found early, and it is usually curable even when at a later stage. Another name for testicular cancer is testis cancer.

Types of testicular cancer

There are two main categories of germ cell tumors that start in the testicles.

  • Seminoma

  • Non-seminoma. A non-seminoma contains any of the following in the tissue:

    • Choriocarcinoma

    • Embryonal carcinoma

    • Yolk sac tumor

    • Teratoma

Each of these can occur alone or in any combination. Sometimes, seminoma cancer can be found as part of a non-seminoma at any percentage level. For example, a tumor that is 99% seminoma and 1% yolk sac tumor is still diagnosed and treated as non-seminoma.

Generally, non-seminomas tend to grow and spread more quickly than seminomas, but prompt diagnosis and treatment are important for both types of tumors. Many germ cell tumors are a mixture of teratoma and other types of germ cell tumors.

Other, less common types of testicular tumors include:

  • Leydig cell tumor

  • Sertoli cell tumor

  • Carcinoma of the rete testis, which is a part of the testicles

This article provides information only on seminomas and non-seminomas of the testicles in men who have reached puberty. Testicular cancer is uncommon in boys who have not yet reached puberty; childhood testicular cancer is approached differently than cancer in teenagers who have been through puberty and adult men.

Other types of cancer, such as lymphoma and leukemia, occasionally spread to the testicles. To find out more about cancer that started in another part of the body and spread to the testicles, read about that specific type of cancer.

Looking for More of an Overview?

If you would like additional introductory information, explore the following item. Please note this link will take you to another section on Cancer.Net:

  • ASCO Answers Fact Sheet: Read a one-page fact sheet (available as a PDF) that offers an easy-to-print introduction to this type of cancer.