Germ Cell Tumors and Sex Cord Stromal Tumors

Germ Cell Tumors and Sex Cord Stromal Tumors


What are germ cell and sex cord stromal cells?

Germ cells and sex cord stromal cells form when a fetus (baby) is developing. A fetus is made from a sperm cell and an egg cell.

Germ cell tumors (GCTs) are also known as germ cell cancer.

  • Germ cells later turn into either sperm in the testicles or eggs in the ovaries.
  • Sex cord stromal cells help germ cells grow.

Germ cell tumors

How common are germ cell cancers?

Germ cell tumors are rare, so very few young people get germ cell cancer. Out of every 100 children and teens under age 20 who have cancer, only 4 of them have germ cell cancer.

Where do germ cell cancers form?

A germ cell tumor (mass) most often forms in the gonads. In females, they’re in the ovaries. In males, they’re in testes (TEST-eez).

Ovaries are the 2 female glands where eggs form. They also make the female hormones estrogen and progesterone.

Testes are the 2 male glands that make sperm and the male hormone testosterone.

Germ cell tumors also can start in the:

  • Abdomen (belly)
  • Spine
  • Chest
  • Brain

Germ cell cancers most often start in young children and adolescents. But young adults also can get them. Testicular germ cell cancers are the most common form of cancer in young men ages 15 to 30.

Germ cell cancer signs and symptoms

The symptoms of germ cell cancers depend on their size and location. Germ cell cancer symptoms can include:

  • A painless lump in the scrotum, if the tumor is in the testicles.
  • A painless lump in the neck, abdomen (belly), lower back, or buttocks (rear end).
  • Sharp pain that will not go away. At first, it seemed to be caused by appendicitis or a twisted testicle.
  • Mild to moderate abdominal pain and constipation, if the tumor is in the ovaries or belly.
  • Shortness of breath or wheezing, if the tumor is in the chest.
  • Headaches, changes in vision, or urinating (peeing) very often, if the tumor is in the brain.
  • Constipation, trouble urinating, or pain, if the tumor is at the base of the spine.
  • Early puberty or menstrual periods that are not regular. Both symptoms are less common. 

Types of germ cell cancers MSK treats

The team in the MSK Kids Rare Solid Tumors Program treats young people with germ cell cancers such as:

  • Testicular seminomas
  • Testicular nonseminomas
  • Mature teratomas of the ovary (dermoid cysts)
  • Immature teratomas of the ovary
  • Dysgerminomas
  • Yolk sac tumors
  • Mixed germ cell tumors
  • Choriocarcinoma
  • Extragonadal (outside the ovaries and testes) tumors
Where do germ cell tumors form? 

As a fetus grows, germ cells migrate (move) along the developing spine. Over time, they arrive in the area where ovaries or testes will form. This happens about 4 weeks after a sperm cell fertilizes an egg.

Some germ cells do not go to the right place and instead settle in another part of the body. Germ cell cancers can start in the spine, chest, and brain.

What causes germ cell tumors? 

We do not know what causes germ cell cancers.

However, some tumors start in children who do not have a normal number of chromosomes. GCTs are more common in children with certain genetic syndromes, such as:

  • Klinefelter syndrome (having 1 or more extra X chromosomes)
  • Swyer syndrome (females with an X and Y chromosome, instead of XX)
  • Turner syndrome [missing or abnormal (not normal) X chromosome]

Sex cord stromal tumors

How common are sex cord stromal tumors?

Sex cord stromal tumors are an even rarer type of ovarian or testicular tumor. Most often, they form in people under age 30.

Sex cord stromal tumors only make up about 7 out of every 100 ovarian tumors. They make up only 3 out of every 100 testicular tumors.

Sex cord stromal tumor signs and symptoms

Symptoms of sex cord stromal tumors can include:

  • A painless lump in the scrotum, if a tumor is in the testicles.
  • A lump in the belly, sometimes with pain.
  • Bloating.
  • Constipation.
  • Very early signs of puberty. This includes growing breasts, body odor, and pubic and underarm hair.
  • Hirsutism (too much hair on some parts of the body).
  • Virilization. This is when girls have features of a male, such as a deeper voice, acne (pimples), or hair on the face.
  • Changes in the menstrual period, such as bleeding that is heavy or not regular.

Types of sex cord stromal tumors MSK treats

Our team treats people with sex cord stromal tumors such as:

  • Granulosa cell tumors (the most common type)
  • Fibromas
  • Thecomas
  • Fibrosarcomas
  • Leydig cell tumors
  • Steroid cell tumors
  • Sertoli cell tumors
  • Sertoli-Leydig cell tumors
What causes sex cord stromal tumors?

Sex cord stromal tumors start in the stroma or sex cords as a fetus develops. The stroma and sex cords are tissues that help support the ovaries. Some of these tumors have been linked to certain genetic mutations (changes or variants) in the DICER1, STK11, and FOXL2 genes.  

Children with rare genetic syndromes called Ollier disease and Mafucci syndrome are more likely to have sex cord stromal tumors.

Why choose MSK to treat your child’s germ cell or sex cord stromal tumors

The importance of diagnosing tumors as cancer or benign

Germ cell tumors and sex cord stromal tumors can be malignant (cancer) or benign (not cancer). Malignant (muh-LIG-nunt) cancers need treatment. Benign (beh-NINE) tumors are not cancer and do not need treatment right away.

MSK Kids doctors are very experienced in caring for all types of GCTs and sex cord stromal tumors. We offer surgery, medicines, radiation therapy, and investigational (being studied) treatments.

These cancers are rare, but MSK doctors treat people with germ cell cancers more often than many other hospitals.

A personal plan of care for your child by a team of experts

We know you’re worried about your child’s future. You may be concerned about how the tumor and its treatment will affect their fertility (ability to have children). We do all we can to provide treatments that work well, with the fewest side effects. Our goal is for your child to have the best life possible.

Your child’s care team will have many kinds of experts. This includes:

  • Surgeons.
  • Pediatric oncologists, who are doctors with special training in cancer in children and adolescents.
  • Endocrinologists (EN-doh-krih-NAH-loh-jists), doctors with special training in endocrine problems. These disorders affect glands and organs that make hormones.
  • Radiation oncologists, who are doctors with special training in using radiation therapy (RT) to treat cancer with radiation.
  • Genetic specialists, who have special training in genetic testing and genetics.

Genetic testing and counseling for kids with germ cell and sex cord stromal tumors

Germ cell cancers and sex cord stromal tumors are linked to certain mutations and inherited syndromes. MSK recommends that children with these tumors have a genetic evaluation. This assessment is done through the MSK Kids Clinical Genetics Service and Pediatric Cancer Predisposition Screening Program in New York City.

Our specialists can help you and your family understand the role of genetics in this cancer. They can also see if any genetic mutations could affect other family members related to you by blood. The genetics team will guide and support you from your first consultation through follow-up care.

New Patient Appointments

Call 833-MSK-KIDS Available Monday through Friday, to (Eastern time)