Testicular Cancer

Approved by the Cancer.Net Editorial Board, 08/2022

Testicular cancer begins when healthy cells in a testicle change and grow out of control, forming a mass called a malignant tumor. The term “malignant” means that the tumor can spread to other parts of the body.

Another name for testicular cancer is testis cancer.

Typically, under the penis in a sac-like pouch called the scrotum, there are 2 testicles. Testicles may also be called testes or gonads. The testicles are part of the reproductive system and produce sperm and testosterone. Testosterone is a hormone that plays a role in the development of male reproductive organs and other male characteristics.

Testicular cancer begins when healthy cells in a testicle change and grow out of control, forming a mass called a malignant tumor. The term “malignant” means that the tumor can spread to other parts of the body.

Another name for testicular cancer is testis cancer.

Most types of testicular cancer develop in the sperm-producing cells known as germ cells and may be referred to as germ cell tumors. Germ cell tumors 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 (in children)
• Very rarely, a small gland in the brain called the pineal gland (mainly in children)

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

There are 2 main categories of germ cell tumors that start in the testicles.

• Seminoma. A tumor is only called a seminoma if it is 100% seminoma. This means that the cancer does not have any of the types of tumor listed below.
• Non-seminoma. A non-seminoma contains at least 1 of the following types of tumor:
  • Choriocarcinoma
  • Embryonal carcinoma
  • Yolk sac tumor
  • Teratoma

Each of these can occur alone or in any combination. Most non-seminomas are a mix of at least 2 different subtypes of germ cell tumor, and all mixed germ cell tumors are categorized as non-seminomas. Non-seminomas may be partly seminoma at any percentage level less than 100%. For example, a tumor that is 99% seminoma and 1% yolk sac tumor is still diagnosed and treated as a 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.

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
• Testicular lymphoma

This section provides information only on seminoma and non-seminoma of the testicles in those who have reached puberty. Testicular cancer is uncommon in those who have not yet reached puberty. Childhood testicular cancer that occurs before puberty is treated differently from cancer that develops after puberty in teenagers and adults.

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.