Germ Cell Ovarian Cancer

Germ cell ovarian cancers arise from the cells in our ovaries that mature into eggs (the germ cells). As a group they are the second most common type of ovarian cancer and account for around 20-25% of all ovarian tumours. The majority of these are a type of tumour called mature cystic teratomas.

Germ cell cancers account for 1-3% of ovarian cancers in Western countries and two thirds of ovarian cancers in women and people diagnosed with ovarian cancer under 30 years old. The proportion of people diagnosed with this type of cancer is much higher in Afro-Caribbean and Japanese people because of the lower frequency of surface epithelial cancers. 

The dysgerminoma is the most common of germ cell cancer. This accounts for approximately 45% of malignant germ cell tumours. Next is immature teratomas and then yolk sac tumours. In women and people younger than 30, germ cell tumours are the most common ovarian cancer diagnosis, and approximately one-third of the germ cell tumours found in those younger than 21 are cancerous (malignant). 

Germ cell tumours are usually affect the one ovary (unilateral), except for benign cystic teratomas and dysgerminomas, which tend to affect both. 

Benign cystic teratoma (dermoid) 

These primarily occur in younger people who are pre-menopausal, but may sometimes occur after the menopause and also post sometimes in children. These teratomas have the ability to produce tissues such as skin, bone, teeth, and hair. 

Dermoids are usually just in the one ovary, but 10-15% affect both ovaries (bilateral). Usually these tumours are asymptomatic, but can sometimes cause severe pain if there is torsion (twisting of the ovary) or if the cyst wall is perforated. 

How are teratomas treated? 

They are usually treated surgically, either by removing just the tumour (ovarian cystectomy) or by removing the whole affected ovary (unilateral oophorectomy). In women and people who are post-menopausal, the treatment for a dermoid tumour usually includes removing the womb, fallopian tubes, and both ovaries.

Immature teratoma 

Immature teratomas are a cancerous tumour and account for as many as 20% of the malignant ovarian tumours found in women and people younger than 20, but less than 1% of all ovarian cancers. They rarely occur in women after the menopause. The prognosis depends on the stage of the disease and grade of the tumour (how aggressive the cancer cells are). Those diagnosed at early stage have good survival rates. 


These are the most common sub-type of cancerous germ cell tumour. They usually occur in women and people who are under 30 years old. Sometimes this type of tumour is discovered during a pregnancy. Most dysgerminomas are bilateral. 95% of people with this type of tumour have a raised LDH level and about 3% have raised BhCG levels. 

If the disease is confined to one ovary, this is usually treated by fertility-sparing surgery to remove the tumour or just the one ovary. Chemotherapy can be used too in treatment of this cancer, usually for when there is residual disease after surgery or if the cancer returns later down the line (recurrent disease). Prognosis for this type of cancer is normally excellent. 

Yolk sac tumours 

Yolk Sac Tumours account for 10% of malignant germ cell tumours. They have this name as they resemble the yolk sac of the rodent placenta, and they are often fast growing. The tumour secretes a-fetoprotein, which is a specific marker useful for identifying and following these tumours. These tumours occur in younger women and people, usually between the ages of 13 months and 45 years- the average age at diagnosis being 19 years old. 

They are usually treated with surgery and combination chemotherapy. The prognosis of this type of cancer depends on the stage at diagnosis, with a survival rate at stage 1 of 70-90%. 


Choriocarcinomas are highly malignant, rare sub-type of germ cell tumours. These tumours mostly develop in women and people younger than 20 years old and treatment is with surgery and combination chemotherapy. 

Embryonal Carcinoma 

Embryonal carcinoma is another rare sub-type of germ cell cancer. It usually occurs in young women and people between the ages of 4 and 28 years. They usually present as large solid masses. Treatment is with a combination of surgery and chemotherapy, and usually has good results. 


Polyembryomas are a type of tumour usually found in the testes, but can sometimes, although rarely, occur in the ovary. 

Struma ovarii and carcinoid 

These two rarer sub-types of germ cell tumours occur primarily in older women and people with ovaries and tend to grow slowly; the prognosis after hysterectomy and removal of both ovaries is usually excellent.  

Mixed Germ Cell Tumours 

These are combinations of any of the germ cell tumours of the ovary. 

Most people with these tumours are young and most of the tumours are unilateral. This often means fertility-sparing surgery can be used as a treatment. Historically people presenting with malignant ovarian germ cell tumours have undergone post-operative chemotherapy. Some exceptions to this are Stage 1A pure dysgerminoma and those with stage 1A, grade 1 immature teratoma, as surgery alone has a high cure rate. There is now a move towards surveillance as an alternative to chemotherapy in certain people, depending on their cancer type and the stage at diagnosis. 

If you have any questions or need any more information, please do contact our Ask Eve Specialist Nurse, Hilary, either by emailing or by phone 0808 802 0019, for free and confidential info and advice.