What Is the Most Common Type of Germ Cell Tumor?

Medically Reviewed on 1/17/2023

What is a germ cell tumor?

Germ Cell Tumor
The removal of a benign or malignant tumor is the primary treatment for germ cell tumors.

Germ cell tumors are benign or malignant tumors that consist of germ cells. Germs cells form in the embryo and mature to become part of the reproductive system in men and women. For women, germ cells form into eggs, and for men, it matures into sperm. Germ cell tumors commonly form in the ovaries and testicles.

Rarely, germ cell tumors can form in other areas of the body, including:

  • Abdomen
  • Chest
  • Low back
  • Tailbone
  • Brain

These tumors are called extragonadal tumors.

Germ cell tumors commonly occur in children, teens, and young adults. It accounts for two to four percent of all cancers in children and adolescents younger than 20 years.

5 common types of germ cell tumors

Five most common types of germ cell tumors include:

  1. Teratomas: The most common benign tumors formed in the extragonadal areas (not in the ovary or testes). This tumor can turn malignant at times.
    • Mature teratomas or dermoid cysts are the common forms of ovarian germ cell tumors.
    • Immature teratomas are rare malignant ovarian growths, accounting for less than one percent of all ovarian germ cell tumors.
    • Doctors may prefer surgery to remove the benign tumor.
  2. Germinomas: These are malignant tumors and have different names based on their location.
    • When formed in the ovaries, germinomas are called dysgerminomas
    • When included in the testes, they are called seminomas.
    • It can form in the middle part of the brain.
  3. Endodermal sinus tumor: Yolk sac tumors commonly found in the ovaries, testes, or tailbone. They spread rapidly to the lymph nodes and other organs. It is the most common malignant germ cell tumor in children.
  4. Embryonal carcinoma: A rare and malignant germ cell tumor that usually develops in the testicle of an adolescent boy. They may develop into other areas in the body. It may either exist as an embryonal carcinoma or may appear alongside other tumor types in a mixed germ cell tumor.
  5. Choriocarcinomas: Consists of cells that develop into the placenta during pregnancy and can affect both the person and their children. Choriocarcinomas may form in the ovaries and testicles but commonly affect the uterus. These are rare and malignant tumors.

What causes germ cell tumors?

Gene mutations in the germ cells can cause uncontrolled growth, leading to a tumor. These germ-cell tumors consist of immature cells that do not develop entirely into healthy ovaries and testicles. Eventually, these cells divide abnormally and become a tumor in the ovaries or testicles. An extragonadal tumor travels outside the gonads (testicles and ovaries).

You could be more likely to get germ cell tumors if you have any of the following:

  • Birth defects in your central nervous system, genitals, lower spine, or urinary tract
  • An undescended testicle (one or both testicles have not dropped into the scrotum)
  • Other family members who had germ cell tumors
  • Genetic conditions, such as Klinefelter’s or Turner’s syndrome, where you have an extra or missing sex chromosome

What are the symptoms of germ cell tumors?

When the germ cell tumor is benign, the person may experience few symptoms or none. Once the tumor grows and spreads, it might create pressure in the abdomen. The symptoms may depend on the location and size of the tumor.

If the tumor is present in the ovaries, the symptoms may include:

The symptoms of testicular germ cell tumors may include:

  • Pain or heaviness in the scrotum
  • Solid, firm lump in a testicle that grows bigger (with or without pain)
  • Oddly shaped testicle
  • Abdominal or groin pain
  • Back pain

The symptoms of extragonadal tumors may include:

  • Troubled breathing
  • Weakness in the legs
  • Trouble moving bowels and urinating
  • Swelling and acute or dull pain in the child’s abdomen


Skin Cancer Symptoms, Types, Images See Slideshow

How is a germ cell tumor diagnosed?

The physicians may use one or more of the following tests or procedures to identify germ cell tumors:

  • CT scan: Takes detailed photos of the body from various angles and projects them in a series. A dye can be administered intravenously or orally to help visualize tissues and organs better.
  • MRI: Uses a magnetic field, radio waves, and a computer to take detailed photos of specific body areas, such as the neck and head.
  • Ultrasound: High-energy sound waves (ultrasounds) bounce off the internal tissues and organs to create echoes. These echoes form a picture.
  • Positron emission tomography (PET) scan: Detects malignant tumor cells within the body. A small amount of radioactive glucose (sugar) is administered intravenously. The PET scanner rotates around the body to take pictures of the areas where glucose has been used in the body. Because malignant tumor cells are more active than normal cells and consume more glucose, they appear brighter in the image.
  • Biopsy: Involves removal of cells or tissues to examine them under a microscope and identify signs of cancer.
  • Bone scan: Involves taking an X-ray of the bone after they have absorbed a special dye. This special dye makes the abnormalities stand out by highlighting them. Bone scans can identify if the tumor has spread to the bone.

3 treatment options for germ cells tumor

  1. Surgery: The removal of a benign or malignant tumor is the primary treatment for germ cell tumors.
    • The surgeon may remove a tumor from the following sites:
      • Affected ovaries
      • Entire ovary
      • Fallopian tubes
      • Affected testicles
  2. Radiation therapy: Utilizes high-energy rays to destroy cancerous cells.
    • Depending on the type of radiation administered, there are two types of radiation therapy:
      • External beam radiation: The radiation comes from a machine kept outside the body.
      • Internal radiation: The doctor puts radioactive material inside the body.
    • Systemic treatments tend to destroy or kill tumor cells in the body completely.
  3. Chemotherapy: Aims to kill or destroy cancer cells or prevent proliferation. Chemotherapy can be either administered orally or intravenously. They enter the bloodstream to reach the cancer cells.
Medically Reviewed on 1/17/2023
Image Source: iStock image

Germ Cell Tumor. https://my.clevelandclinic.org/health/diseases/23505-germ-cell-tumor

Germ Cell Tumors. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=90&contentid=p02725