Benign Ovarian Tumours

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Benign ovarian tumours are non-cancerous tumours of ovaries. Benign ovarian tumours consist of ovarian cyst and ovarian tumours. Ovarian cyst has been dealt separately under the topic “Ovarian Cyst”. Both ovarian cyst and benign ovarian tumour are commonly seen in reproductive age group. Majority of benign ovarian tumours do not cause any symptoms. Benign ovarian tumours can be incidentally diagnosed when you go for routine check-up. Not all benign ovarian tumours need treatment.

Where are the ovaries situated in the body?

There are two ovaries situated on either side of the uterus. 

  • Ovaries main function is to make female hormones and release an egg regularly each month.

  • Hormones are generated in the ovary from menarche (first onset of menstruation) until menopause (when menstruation stops).

  • Each ovary is situated in its specific place beside the uterus called ovarian fossa.

  • Ovaries are attached to the uterus with help of ovarian ligament. 


Ovary has three main layers:

1. Ovarian surface – this is the outermost covering of the ovary and is formed by simple cuboidal epithelial cells (known as germinal epithelium). Just underneath this layer is a dense connective tissue called ovarian capsule.

2. Ovarian cortex – the inner most part of ovary is comprised of a connective tissue stroma and numerous ovarian follicles. Each follicle contains an egg (oocyte), surrounded by a single layer of cells known as follicular cells.


3. Medulla – medulla is the inner most part of the ovary and is formed by loose connective tissue and has a rich neurovascular network (nerves and vessels enter ovary through medulla), which enters via the hilum of the ovary.

What are the types of ovarian tumours?

Ovarian tumours are generally divided into three main groups:

  1. Functional

  2. Benign (non-canceous)

  3. Malignant (cancer)

Of all the ovarian tumours incidence of functional cysts is about 24%, benign tumours 70% and malignant tumours 6%.

Classification of benign ovarian tumours: Depending from which part of the ovary the tumour arises there are different classification of benign ovarian tumours.

I. Benign tumour of epithelial origin: 60% of  benign ovarian tumours are of epithelial type and are derived from the ovarian surface epithelium. Again different types of ovarian tumour can arise from the outer epithelial layer of cells such as:

a. Serous cystadenoma:

  • They are commonly seen in women aged between 40-50 years.

  • About 15-25% of these tumours develop simultaneously in both ovaries and about 20-25% of them can be malignant.

b. Mucinous cystadenoma:

  • The most common large ovarian tumours are of mucinous type and they can grow to enormous size filling the whole abdomen.

  • This type of tumours are filled with mucinous material (jelly like) and when the tumour ruptures / leaks, the jelly escapes into the tummy and may cause pseudomyxoma peritonei. Majority of the times they may be multilocular (multiple cystic tumours combined).

  • They are commonly seen in the 20-40 age group. About 5-10% these tumours develop simultaneously in both ovaries and around 5% will be malignant.


II. Benign tumours of germ cell origin: 

  • Ovary has millions of primitive germ cells in them (primitive germ cells means eggs which are in the initial stages of development), with each menstrual cycle one primitive germ cell is selected and nourished to become an egg (oocyte). Germ cell tumours are those tumours that arise from the primitive germ cells. 

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  • Both benign and malignant tumours can arise from these germ cells. Types of germ cell tumours are dysgerminoma, teratomas, embryonal tumours, endodermal sinus tumour, choriocarcinoma and mixed cell types. Of all these types only teratomas can both benign and malignant. Here we will be discussing only benign teratoma also known as mature teratoma or as dermoid cyst. 

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  • These germ cell tumours are most commonly seen in young women (teenage girls) but the age can range from 14-54 years.

  • A benign mature teratoma are commonly seen in single ovary and 20% are noted in bilateral ovaries at the time of presentation.

III. Benign non-cancerous tumours which are solid in nature:

  • Fibroma: ovarian fibroma are the most common benign solid tumour of the ovary. Commonly seen in perimenopause and post-menopause women, the median age have been reported as 52 years. Less than 1% of fibromas are malignant.  Sometimes they are associated with Meigs' syndrome which is defined as the triad of benign solid ovarian tumour, ascites and pleural effusion .

  • Thecoma: this is again a rare type of ovarian tumour and less than 1% are malignant. The incidence of this tumour is reported to be highest among pre- and postmenopausal women of 50 - 60 years of age. Unlike its malignant counterpart benign thecomas rarely present’s with hirsutism and androgenic features.

  • Adenofibroma: it’s extremely uncommon benign tumour of ovary.

  • Brenner's tumour: is another a rare non-cancerous tumour.

Over 95% are benign and more than 90% are seen in unilateral ovary.


  • Benign ovarian tumours is seen in 30% of women with regular menses (eg, luteal cysts as incidental findings on pelvic scans) and 50% of women with irregular menses.

  • Commonly seen in premenopausal women; they may also occur perinatally, but uncommon in premenarchal and postmenopausal women.

  • A large proportion of cysts in women of childbearing age are non-malignant type & mainly of functional type which usually tending to resolve over time. 

What are the risk factors?

  • Exact cause for benign ovarian tumour is not known, but there are risk factors which have some association with ovarian tumours such as:

  • Obesity.

  • Tamoxifen therapy (commonly used as breast cancer treatment) has been associated with an increase in persistent ovarian cysts.

  • Early menarche (early menarche is defined from 9 to 11.5 years).

  • History if infertility.

Dermoid cysts can sometime run in families.

What are the symptoms?

Most of the times they do not cause any symptoms, it could be accidentally picked up on ultrasound. But, sometimes if the ovarian tumours are big it can symptoms such as:

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Pain during periods

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Tummy looks swollen; sometimes you can feel the lump in the tummy

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Pain during sex


Lower tummy pain or discomfort

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Rarely you can have severe pain and vomiting, this can happen when the ovary twists on itself. This may require urgent medical treatment.

Can have pressure on bladder and you may have feeling like you want to pass urine frequently.

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Ascites (fluid in tummy) - suggests malignancy or Meigs' syndrome.

Endocrine manifestations – some of hormone secreting tumours may cause virilisation, menstrual irregularities or postmenopausal bleeding. This is uncommon though.

What tests will be required for diagnosis?

Once your doctor notes your symptoms first they would do physical examination, feeling your tummy and internal examination. Based on your symptoms you may be advised following tests:

  1. Pregnancy test: during reproductive age we need to remember that pregnancy mainly “ectopic pregnancy” can present as adnexal mass (ovarian mass).

  2. Ultrasound (USG): a pelvic ultrasound is the first radiological test that would be advised and this is the single most effective way of evaluating an ovarian mass. Transvaginal ultrasound (TVS) is preferable due to its increased sensitivity over transabdominal ultrasound (TAS).

  3. CT or MRI scan: if USG results are not definitive or suspicious then you may be advised for CT or MRI scan. 

  4. Diagnostic laparoscopy: in some emergency situation diagnostic laparoscopy, wherein a telescope is placed in your tummy through small hole to diagnose exactly as to what is the cause. 

  5. Blood test: 

  • Cancer antigen 125 (CA 125): CA 125 may be advised if the ovarian mass is looking suspicious. It is very important to note that CA 125 is not very reliable in differentiating ovarian tumor from benign and malignant. CA 125 can also be elevatied in other conditions such as, endometriosis, liver cirrhosis, uterine fibroids, menstruation, pregnancy, and other non-gyne malignancies (pancreatic, bladder, breast, liver, lung)

  • Lactate dehydrogenase (LDH), alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG): these tumour markers should be measured in all women under the age of 40 with a complex ovarian mass because of the possibility of germ cell tumours.

What are the treatment options?

When simple ovarian cysts are diagnosed based on ultrasound findings majority do not require treatment.

Expectant management - ‘watching and waiting’

  • If you have a simple cyst that measures <5 cm in diameter: 

Treatment is not necessary. These cysts usually disappear on their own after a few months and ou are unlikely to need a follow-up ultrasound. 

  • If you have a simple cyst that measures 5–7cm in diameter: 

You would be offered follow-up, usually an ultrasound scan (USG) after a year. 

  • If you have a simple cyst that measures more than 7 cm in diameter:

You will need further tests, such as magnetic resonance imaging (MRI). 


Medical management:

Oral contraceptives (OCP): The oral contraceptive pill is no more recommended, as its use has not been shown to promote the resolution of functional ovarian cysts, hence watchful waiting for two or three cycles is appropriate and if cysts persist then surgical management is often indicated.


Surgery may be indicated if conservative measures fail or criteria for surgery are met, surgical management for benign ovarian tumours is generally very effective and has minimal effect on reproductive capacity. 

  • Ovarian cystectomy (remove only the cyst and retain the ovary): when ovarian cysts are clear your doctor may offer to do only ovarian cystectomy 

  • Oophorectomy: if the cysts or benign tumours are really big in size that indicates that the normal ovary  will be distorted and hence you may be advised for to oophorectomy (removal of full ovary). 


Mode of surgery would be - laparoscopic or robotic surgery for benign ovarian tumours is usually preferable to open surgery.

  • During pregnancy although most adnexal masses are benign, when surgical management is chosen, laparoscopy can be safely performed after first trimester.

  • If you have had an ovarian torsion: you would initially be treated by laparoscopy with untwisting of the affected ovary and if the ovary has not had enough blood supply for a long period of time the possible oophorectomy (removal of whole ovary).

Immediate surgical intervention is indicated:

  • For a haemorrhagic cyst

  • Torsion or rupture of adnexal mass 

  • Laparoscopy may be converted to laparotomy (open surgery) when malignancies is suspected.

Complications of ovarian tumours:

  • Torsion

  • Haemorrhage

  • Rupture of an ovarian cyst

  • May lead to infertility


Robotic surgery

Open surgery