Ovarian Cyst

Ovarian Cyst

What is Ovarian Cyst?

Ovarian cysts are sac filled with fluid or semifluid materials that arise within the ovaries. These cysts can develop in any stage of life, from neonatal to postmenopausal. However, most ovarian cysts occur during hormone active periods of development.

Woman can develop a single or multiple ovarian cysts of various sizes.  Most of the time the cysts are benign (non-cancerous) and go away on its own. However, they may rupture or cause bleeding and pain. In such cases, surgery is recommended. Very rarely, cysts can turn malignant (cancerous).

Types of Ovarian Cyst?

Ovarian cysts form for numerous reasons. There are several different types of cysts as listed below:

Functional Cysts

Each month, the ovary produce cyst like structures called follicles. These follicles produce female hormones (estrogen and progesterone) and produce an egg when you ovulate. Occasionally a normal follicle keeps growing and form functional cysts. Functional cysts are often harmless and will resolve on their own. There are 3 forms of functional cysts:

-         Follicular Cyst: During ovulation, usually the follicle will rupture and release the egg into the fallopian tube in search of sperm for fertilization. When the follicle fails to release the egg and rupture, it may grow and form a follicular cyst.
-         Corpus Luteum Cysts: After the release of the egg, the remnant follicle is then called a corpus Luteum and begins to produce estrogen and progesterone in preparation for conception. Sometimes during release of the egg, fluid may be trapped inside and result in Corpus Luteum cysts. Ovulation inducing drugs (serophene, clomid) used may induce formation of corpus luteum cysts.
-         Theca-Lutein Cysts: these cysts develop as a result of an overstimulation by the hormone human chorionic gonadotropin (hCG). When hCG level drops, the cysts may resolve spontaneously. It is associated with conditions like gestational trophoblastic disease (hydatiform mole and choriocarcinoma which are tumors that secrete hCG), multiple pregnancy and with usage of ovarian hyperstimulation drugs. These cysts have a higher risk of bleeding, rupture and torsion.

Luteoma of Pregnancy

These are very rare non-cancerous ovarian cyst due to the hormonal effects of pregnancy. This happens due to the surge in androgens (testosterones) in certain females. These usually resolve after pregnancy.

Teratomas (Dermoid Cysts)

Teratomas are a form of germ cell tumors make up of 3 embryonic germ layers i.e. ectoderm, endoderm and mesoderm. Hence teratomas may contain different tissues such as hair, cartilage, teeth, fat and bones. These cysts are non-cancerous, may cause torsion and pain or get inflamed.


These non-cancerous cysts develop from within the ovary and may contain liquid or mucous material. They can grow to very large sizes.


Endometriomas are blood-filled cysts as a result of the condition endometriosis. Endometriosis is a condition whereby the endometrial cells (uterine cells) are found outside the uterus. It usually presents with a triad of dyspareunia (pain during sex), dysmenorrhea (painful menses) and menorrhagia (heavy menses).

Polycystic Ovarian Syndrome

Polycystic Ovarian Syndrome is a condition whereby the ovary is filled with multiple cysts. It will be discussed further in another page on this blog.

Ovarian Cancerous cyst

These are rare and often arise from the surface epithelium of the ovary. Others include germ cell tumors and sex cord stromal tumors. Most of the time 99% cysts are non-cancerous. 

Risk factors for ovarian cyst formation

-         Ovarian induction agents used in infertility such as clomiphene citrate or letrozole which hyper stimulates the ovaries to ovulate

-         Tamoxifen can cause formation of benign follicular cysts

-         Pregnancy surge in hCG hormone will induce ovarian cysts

-         Hypothyroidism will induce ovarian cyst formation as the alpha sub-unit of thyroid stimulating hormone (TSH) resembles hCG.

-         Maternal gonadotropin hormones may cross to the fetus and cause neonatal and fetal ovarian cysts

-         Cigarette smoking increase risk of functional cysts
-         Tubal ligation sterilization is associated with increased risk of functional cysts.

Risk factors for cancerous ovarian cyst

-         Strong family history of ovarian cancer
-         Increasing age
-         White race
-         Nulliparity (nil pregnancy history)
-         Infertility
-         Patients with BRCA gene mutations
-         Patients with history of breast cancer 

Clinical presentation of ovarian cysts

Most ovarian cysts do not cause any symptoms and will resolve with time. Most of the time they are discovered incidentally during pelvic examination or ultrasound examination. Larger cysts tend to cause more symptoms.

Pain may be felt by patient if the cyst grows rapidly/ruptures bleed or cause torsion (twisting of the ovary cutting off the blood supply).

Pressure Symptoms may be felt by patient due to the pressure effect of cysts on surrounding organs. It may cause abdominal fullness or indigestion, early satiety, pain during sexual intercourse, urination frequency, bowel movements difficulties, urge to defecate and irregular menses.

Physical Findings of Ovarian Cysts

You doctor will do a thorough examination on you. On examination of the abdomen and pelvis, a large cyst may present as a mass, tenderness and as ascites in cancerous cysts. Ruptured/bleeding cyst or ovarian torsion usually present as an acute abdomen with pyrexia, rebound tenderness, guarding requiring surgical intervention.

Cancerous cysts will present as a mass in the abdomen, ascites in abdomen, enlarged lymph nodes and sometimes with pleural effusion. Patients are often very cachexia and breathless. 

Investigations for Ovarian Cysts

Lab Tests:
-         Urine Pregnancy Test: to rule out ectopic pregnancy or cysts associated with pregnancy
-         Urinary analysis: urinary tract infection and renal stones may also cause pelvic pain like cysts
-         Full blood count: will reveal anemia due to a bleeding cyst or raised white cell count in the case of infection from a torsion or ruptured cyst
-         Endocervical swab: to rule out sexually transmitted infections that will cause pelvic pain
-         Hormone levels: LH, FSH, Estradiol and testosterone can be measured as certain cysts are formed due to hormonal surge
-         Ca125: Cancer Antigen 125 is a protein expressed on the cell membrane of normal ovarian tissue as well as in ovarian cancers. It can be raised in non-cancerous conditions like endometriosis, pelvic inflammation, menstruation, pregnancy, liver, kidney and lung diseases. It can also be raised in other cancers such as liver, stomach, lung, pancreas, uterus, breast and colon.

Imaging studies
-         Ultrasonography: This is a non-invasive imaging using sound waves to visualize the ovary cyst. An ultrasound will aid the doctor to visualize the cyst morphological characteristics to differentiate the simple cysts, complex cysts and cancerous cysts.

Normal cysts are usually 2.5-5 cm in length, 1.5-3 cm wide and 0.6-1.5 cm thick. During the follicular phase, ultrasound may detect multiple cysts in the ovary.

Simple cysts are non-cancerous cysts. On ultrasound, they often appear to have a thin round wall, unilocular (single compartment) appearance and hypoechoic or anechoic. These cysts can vary from 2.5-15 cm in diameter.

Complex Cysts are often multilocular (more than 1 compartment), projections into the lumen, thickened wall or abnormalities with the cyst contents. They can be non-cancerous or cancerous cysts and warrant further investigations.

Other cysts like teratomas, hemorrhagic cysts and Endometriomas have their own characteristics on ultrasound.

-         CT scan: does not offer any further information as compared with ultrasound. It is best in imaging bleeding cysts or cyst ruptures and also for staging of ovarian cancer. Not recommended in pregnant women due to radiation risk.

-         MRI Scan: Safe in pregnant women. In conjunction with ultrasound it offers more specific imaging. It has better soft tissue contrast as compared with CT scan particularly blood or fat products allowing physicians to have a better idea of the origin of the cysts.

Invasive procedures:

-         Culdocentesis: Needle aspiration through the vaginal wall behind the uterine cervix to the cysts. The fluid is then sent for cytology studies. Due to the risk of complications like perforation of bowels, trauma to kidney and abscess rupture, this is usually not recommended. Ultrasound findings are usually sufficient.

-         Laparoscopic Surgery: Surgeon will make small incisions, and pass camera into the abdomen for direct visualization of cyst. The cyst can be biopsied or removed at the same settings. Laparoscopic surgery often has earlier healing as compared with laparotomy.

Treatment for Ovarian Cysts

Simple functional cysts found on ultrasound are usually monitored with periodic ultrasound and do not require surgical intervention unless they cause symptoms. Most of the time they will resolve with time.

In post-menopausal patients who have simple cysts smaller than 5 cm and a normal CA 125 levels can be monitored with periodic ultrasound. Any rise in CA125, increase in size of cysts, change in complexity of cyst structure and suggestion of cancerous change of cyst will warrant a surgical intervention. 
Removal of the ovaries and often uterus (bilateral salpingo-oophorectomy) are suggested in this group of patients as risk of cancer increases with age.

Pre-menopausal patients with simple cysts smaller than 8 cm, normal CA125 level and have no symptoms can be monitored with periodic ultrasound too. Hormone therapy like oral contraceptives has not been found to resolve cysts.

Ovarian cysts in neonates should be followed up with serial ultrasound to look for signs of regression, increase in size and complications. Surgery is indicated if there are signs of complications like bleeding or torsion and if the cyst is larger than 5cm.

Pregnancy associated cysts like follicular cysts and corpus luteum will resolve by 14 to 16 weeks of gestation. Any mass that persist longer, increase in size or shows signs suggestive of cancer should be investigated. Surgical removal is indicated if the cyst is cancerous, rapidly growing and causing symptoms like pain.

For patients who experience pain, pain killers like paracetamol, Non-steroidal anti-inflammatory drugs and opioids can be used to control pain.

Surgery can be done via laparotomy (open incision technique over lower abdomen) or laparoscopy (minimally invasive surgery using small incisions as ports to introduce camera and surgical instrumentations. Surgery may be done to remove the cyst alone (cystectomy) or the ovary and the fallopian tube (salpingo-oophorectomy) and the two ovaries and uterus (bilateral salpingo-oophorectomy). The extent of surgical intervention depends on the patient’s condition and is best discussed with your gynecologist.

Laparoscopy is now more preferred as the recovery time is faster and less side effects and complications. The surgery allows the surgeon to assess the cyst directly, obtain peritoneal washings for cytology, to do staging if it’s a cancerous ovary tumor as well as to assess the other ovary and surrounding organs.

Prevention and Screening

The use of oral contraceptives does reduce the risk of ovarian epithelial cancer. It also protects against the development of functional ovarian cysts however it does not regresses pre-existing functional cysts.

There’s no definite way to prevent the formation of ovarian cysts. Annual gynecological examination is recommended to detect any abnormalities early.
Ovarian Cancer will be discussed in another page.


1.      www.mayoclinic.com
2.      www.acog.org
3.      Knight JA, Lesosky M, Blackmore KM, Voigt LF, Holt VL, Bernstein L, et al. Ovarian cysts and breast cancer: results from the Women's Contraceptive and Reproductive Experiences Study. Breast Cancer Res Treat. May 2008; 109(1):157-64. [Medline].
4.      Bosetti C, Scotti L, Negri E, Talamini R, Levi F, Franceschi S, et al. Benign ovarian cysts and breast cancer risk. Int J Cancer. Oct 1 2006; 119(7):1679-82. [Medline].
5.      Clement PB. Anatomy and histology of the ovary. In: Kurman RJ, ed. Blaustein's Pathology of the Female Genital Tract. 5th ed. New York, NY: Springer-Verlag; 2002:649-673.
6.      Katz VL. Comprehensive Gynecology. 5th ed. Philadelphia: Mosby Elsevier.; 2007:1098-103.

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Ovary Diseases

The female reproductive system consists of the ovaries, fallopian tubes, uterus, cervix and the vagina.

Ovaries produce eggs and female hormones (estrogen and progesterone). These are important in the regulation of menstrual cycles, pregnancy as well as feminine characteristics such as breasts. Each ovary is about the size of an almond.

From menarche to menopause, the ovaries will release eggs and the female hormones. When menopausal the ovaries will stop releasing the eggs and make lower levels of the female hormones resulting in post-menopausal symptoms.

Ovarian diseases involved any disorders with the ovaries. It includes Ovarian Cancer, Ovarian Cyst, Polycystic Ovary Syndrome, Premature Ovarian Failure and also Ovarian Torsion. We will discuss each condition in details in this blog.