Germ cell tumours

This type of ovarian tumour occurs in five per cent of ovarian cancer cases.

Germ cell tumours arise in the cells that form eggs within the ovaries, and tend to be found in younger women.

There are a number of different subtypes of germ cell tumour, which means each subtype is quite rare. Overall they represent around five per cent of ovarian tumours.

Treatment should take place at a centre with expertise in dealing with this particular type of ovarian tumour. The majority of germ cell tumours (60–70 per cent) are diagnosed at stage I and these early stage tumours are often treated with surgery alone. Surgery combined with chemotherapy may be used to treat more aggressive types or more advanced stage tumours.

The different subtypes can behave and respond differently to treatment.


This most commonly affects women of reproductive age.


There are two main types of teratoma tumour – mature and immature.

Mature teratoma
Mature teratomas (or dermoid cysts) are most commonly diagnosed in women between their teenage years and 40s. The cyst is normally present at birth, but grows very slowly and so may not be noticeable until much later. These cysts are usually benign (non-cancerous) and can be treated by surgery alone. The type of operation you receive will depend on your age, the size of the cyst and whether cancer is suspected. Your specialist will advise on the options for your individual situation. 

Immature teratoma
Immature ovarian teratomas are usually diagnosed before a woman is in her early 20s. This type of cancer is rare and is usually treated with surgery and chemotherapy. In most cases it's necessary to remove the affected ovary; however, you can often retain your fertility as the other ovary and uterus (womb) are left alone.

Ovarian yolk sac tumour (OYST)

OYST of the ovary, also known as endodermal sinus tumour, is a primitive malignant (cancerous) germ cell tumour (GCT) that occurs in girls and young women.

Treatment usually consists of surgery to remove the primary tumour, and chemotherapy. In young women, it's sometimes possible to perform fertility-sparing surgery to preserve the possibility of becoming pregnant later on.

Mixed germ cell tumour (MGCT)

These are malignant (cancerous) ovarian tumours made up of two or more types of germ cell tumours.

Other types of germ cell ovarian tumours
  • Monodermal and highly specialised
  • Embryonal carcinoma
  • Polyembryoma 


Last reviewed: June 2018

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