Germ cell tumours

About 5 in every 100 cases of ovarian cancer are germ cell tumours.

Germ cell tumours start in the cells that form eggs within the ovaries. They tend to develop in those who are younger. 

There are a number of different subtypes of germ cell tumour, which means each subtype is quite rare. They represent around five per cent of ovarian tumours (5 in 100 cases of ovarian cancer). 

About 6 in every 10 cases of germ cell ovarian cancer are diagnosed at stage 1 and these early-stage tumours are often treated with surgery alone. Some subtypes of germ cell cancers or more advanced tumours are treated with both surgery and chemotherapy.  

The different subtypes can behave and respond differently to treatment. 


Dysgerminoma tumours most commonly affects those of reproductive age (from about age 15 to 45).


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

Mature teratoma
Mature teratomas (or dermoid cysts) are most commonly diagnosed between someone’s 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 with surgery alone. The type of surgery you have will depend on your age, the size of the cyst and whether cancer is suspected. Your doctor will tell you about the options for your own situation.  

Immature teratoma
Immature ovarian teratomas are usually diagnosed before someone’s early 20's. This type of cancer is rare and is usually treated with surgery and chemotherapy. In most cases the affected ovary will need to be removed. But you are often able to keep your fertility as the other ovary and the womb aren’t removed. 

Ovarian yolk sac tumour (OYST)

OYSTs, also known as endodermal sinus tumours, are a malignant (cancerous) germ cell tumour that usually happen in children and younger adults

OYSTs are usually treated with surgery to remove the primary tumour, and chemotherapy. In those who are younger, it's sometimes possible to perform fertility-sparing surgery to keep the possibility of becoming pregnant in future. 

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 
Rachel and Val Target Ovarian Cancer nurse advisers

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Last reviewed: May 2022

Next review: May 2025

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