A cyst is a closed, saclike structure, an abnormal pocket of fluid, similar to a blister that contains liquid, gaseous, or semi-solid material.
A cyst is located within the tissue, can develop anywhere in the body and may vary in size – some are so tiny they can only be observed through a microscope, while others may become so large that they displace normal organs.
If the sac is filled with pus it is an abscess. Some cysts are solid and may be called tumours.
An ovarian cyst is an accumulation of fluid within an ovary that is surrounded by a very thin wall. Any ovarian follicle that is larger than about 2cm is an ovarian cyst.
These can range widely in size, from being as small as a pea to larger than an orange. In rare cases, ovarian cysts can become so large that the woman looks pregnant.
The majority of ovarian cysts are benign. Most premenopausal women and up to 15% of postmenopausal women are found to have ovarian cysts, but they typically occur most frequently during the childbearing years.
In some cases, ovarian cysts cause pain and bleeding. If it is over 5cm in diameter, it may need to be surgically removed.
There are two main types of ovarian cysts:
-Functional ovarian cysts – the most common type. These harmless cysts form part of the menstrual cycle and are short-lived.
-Pathological cysts – these are cysts that grow in the ovaries. They may be harmless (benign) or cancerous (malignant).
There is no definite way of preventing ovarian cyst growth. However, regular pelvic examinations, which allow for early treatment if needed, usually protect the woman from complications. As most ovarian cysts present no signs or symptoms, they frequently go undiagnosed.
This also makes it difficult to estimate incidence and prevalence of the condition. Sometimes, even without symptoms, a cyst may be diagnosed during an unrelated pelvic examination or ultrasound scan.
The causes are different for each type of ovarian cyst, so we have to look at them one type at a time.
FUNCTIONAL OVARIAN CYSTS
There are two types of functional
1. Follicular cysts Follicular cysts are the most common type of ovarian cyst. A female human has two ovaries which release an egg every month. The egg moves into the uterus (womb), where it can be fertilised by a male sperm. The egg is formed in the follicle, which contains fluid to protect the growing egg. When the egg is released, the follicle bursts. In some cases, the follicle either does not shed its fluid and shrink after releasing the egg, or does not release an egg. The follicle swells with fluid, becoming a follicular ovarian cyst. Typically, one cyst appears at any one time and normally goes away within a few weeks (without treatment).
2. Luteal ovarian cysts These are less common. After the egg has been released it leaves tissue behind (corpus luteum). Luteal cysts can develop when the corpus luteum fills with blood. In most cases, this type of cyst goes away within a few months. However, it may sometimes rupture, causing pain and internal bleeding.
Dermoid cysts are the most common type of pathological cyst for women under 30 years of age. Cystadenomas are more common among women aged over 40 years
1. Dermoid cysts (cystic teratomas) Dermoid cysts are usually benign. They develop from a totipotential germ cell – in other words, the cell can give rise to all orders of cells necessary to form mature tissues. Dermoid cysts contain hair, skin, bone and other tissues (sometimes even teeth). A totipotential germ cell can develop in any direction. They are formed from cells that make eggs. These cysts need to be removed surgically.
2. Cystadenomas Cystadenomas are ovarian cyststhat develop from cells that cover the outer part of the ovary. Some are filled with a thick, mucous substance while others contain a watery liquid. Rather than growing inside the ovary itself, cystadenomas are usually attached to the ovary by a stalk. By existing outside the ovary, they have the potential to grow considerably. Although they are rarely cancerous, they need to be removed surgically.
The following conditions may increase the risk of developing ovarian cysts:
Endometriosis is a condition in which cells that are normally found inside the uterus (endometrial
cells) are found growing outside of it. That is, the lining of the inside of the uterus is found
outside of it. Endometrial cells are the cells that shed every month during menstruation, and so endometriosis
is most likely to affect women during their childbearing years. Women with this condition have a higher risk of developing ovarian cysts.
-Polycystic ovarian syndrome In this condition, many small and harmless cysts develop on the ovaries, caused by a problem with hormone balance produced by the ovaries. There is also a higher risk of developing ovarian cysts.
-Pelvic pain -A ruptured ovarian cyst may present similar signs and symptoms to those of appendicitis or diverticulitis. In the vast majority of cases, ovarian cysts are small and benign; there will be no signs or symptoms. Even if there are symptoms, they alone cannot determine whether a patient has an ovarian cyst. There are several other conditions with similar signs and symptoms, including endometriosis, pelvic inflammatory disease, ectopic pregnancy or ovarian cancer. A ruptured ovarian cyst may present similar signs and symptoms to those of appendicitis or diverticulitis.
-Irregular menstruation – periods may also become painful, heavier or lighter than normal
-Dyspareunia – pelvic pain during sexual intercourse. Some women may experience abdominal pain and discomfort after sex
-Pain when passing a stool (doing a poo)
-Pressure on the bowels
-Pregnancy symptoms, including breast tenderness and nausea
-Bloating, swelling, or heaviness in the abdomen
-Problems fully emptying the bladder
Pressure on the rectum or bladder – the patient may have to go to the toilet more often, either to urinate or pass a stool
-Hormonal abnormalities – in rare cases, the body may produce abnormal amounts of hormones, resulting in changes in the way the breasts and body hair grow.
-Torsion – the stem of an ovary can become twisted if the cyst is growing on the stem, blocking the blood supply to the cyst and causing severe pain in the lower abdomen.
-Bursting – if the ovarian cyst bursts, the patient will experience severe pain in the lower abdomen. If the cyst is infected, pain will be worse. There may also be some bleeding.
– Cancer – in rare cases, an ovarian cyst may be an early form of ovarian cancer.
When an ovarian cyst is suspected from history and examination, the following diagnostic tests may also be ordered:
-Ultrasound An ultrasound will be carried out to help the doctor make a diagnosis. A probe (transducer) is placed on the abdomen, over where the ovaries are. Sometimes the probe may be placed inside the vagina. In both cases, the doctor is observing the ovaries on a video screen. This test can help the doctor determine whether there is a cyst, and whether it is solid, filled with fluid (or both).
-Blood test If there is a tumour present, blood level of CA125 will be elevated. High CA125 levels could also mean the patient has ovarian cancer.
Pregnancy test A positive pregnancy test result may suggest a corpus luteum cyst.
Laparoscopy A thin, lighted instrument called a laparoscope is inserted into the patient’s abdomen through a small incision (skin cut). If the doctor spots an ovarian cyst, they may remove it there and then.
Sometimes watchful waiting is recommended, especially if the woman is premenopausal, and she has a small functional cyst (2cm-5cm). An ultrasound scan will be carried out about a month or so later to check it, and to see whether it has gone. Postmenopausal women are monitored with ultrasound scans, as well as blood tests to check their CA125 levels. The approach depends very much on the size of the cyst and whether it has changed over time.
– Oral contraceptives The doctor may prescribe them to reduce the risk of new cysts developing in future menstrual cycles.
-Surgery If the cyst is growing or persists through three menstrual cycles, the doctor may recommend that it be surgically removed.
-Cancer treatment If the cyst is cancerous, the patient may need to have more organs and tissue removed, including the ovaries, uterus, the omentum and some lymph nodes.