Germ cell tumours

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Germ cells are the type of cells that develop into eggs (in the ovaries) or sperm (in the testicles). Germ cell tumours affect these germ cells.

Germ cell tumours can develop before or after birth. They can form in the ovaries or testicles, or in other parts of the body. This is because sometimes, when babies are in the womb, germ cells travel to other parts of the body. Germ cell tumours can release hormones or enzymes that can cause symptoms.

Germ cells tumours are named for where they are formed:

  • gonadal germ cell tumours form in the ovaries or testicles
  • intracranial or intraspinal germ cell tumours form in the brain or spinal column
  • extracranial, extragonadal germ cell tumours tend to form along the midline of the body, such as
    • in the bottom of the spine
    • at the back of the belly
    • between the lungs
    • on the neck.

Germ cell tumours can be one of three types.

Mature teratomas

Mature teratomas are benign tumours that are not likely to become cancerous. They usually occur:

  • in the bottom part of the spine in babies
  • in the ovaries of girls when they reach puberty.

Mature teratomas are the most common type of extracranial germ cell tumours.

Immature teratomas

Immature teratomas might become cancerous. They usually occur in the same places as mature teratomas:

  • in the bottom part of the spine in babies
  • in the ovaries of girls when they reach puberty.

They can contain several types of cells, such as bone, hair and muscle.

Malignant germ cell tumours

Malignant germ cell tumours are cancerous. They are divided into germinomas and nongerminomas, depending on the type of hormone they release.

Germinomas are the most common type of intracranial germ cell tumour.