An ovarian cyst happens when fluid accumulates within a thin membrane inside the ovary. The size can range from as small as a pea to larger than an orange.
A cyst is a closed sac-like structure. It is divided from surrounding tissue by a membrane. It is an abnormal pocket of fluid, similar to a blister. It contains either liquid, gaseous, or semi-solid material. The outer or capsular portion of a cyst is called the cyst wall.
It is different from an abscess because it is not filled with pus. A pus-filled sac is an abscess.
Most ovarian cysts are small and harmless. They occur most frequently during the reproductive years, but they can appear at any age.
There are often no signs or symptoms, but ovarian cysts can sometimes cause pain and bleeding. If the cyst is over 5 centimeters in diameter, it may need to be surgically removed.
Fast facts on ovarian cysts:
An ovarian cyst is a buildup of fluid within an ovary surrounded by a thin shell, or membrane.
Ovarian cysts are usually harmless, but a large one may need to be removed.
There are two main types of ovarian cysts: functional ovarian cysts and pathological cysts.
In most cases, ovarian cysts will cause no signs or symptoms.
There are two main types of ovarian cysts:
Cysts can develop anywhere on the body, some may be microscopically small and others very large.
Functional ovarian cysts – the most common type. These harmless cysts form part of the female’s normal menstrual cycle and are short-lived.
Pathological cysts – these are cysts that grow in the ovaries; they may be harmless or cancerous (malignant).
The causes are different for each type. We will look at each type in turn.
Functional ovarian cysts
There are two types of functional ovarian cysts:
1) Follicular cysts
Follicular cysts are the most common type. A woman has two ovaries. The egg moves from an ovary into the womb, where it can be fertilized by 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 it does not release an egg. The follicle swells with fluid, becoming a follicular ovarian cyst.
One cyst normally appears at any single time, and it normally goes away within a few weeks.
2) Luteal ovarian cysts
These are less common. After the egg has been released, it leaves tissue behind, known as the corpus luteum. Luteal cysts can develop when the corpus luteum fills with blood. This type of cyst normally goes away within a few months. However, it may sometimes split, or rupture, causing sudden pain and internal bleeding.
There are two types of pathological cysts:
1) Dermoid cysts (cystic teratomas)
A dermoid cyst is usually benign. They are formed from the cells that make eggs. These cysts need to be removed surgically. Dermoid cysts are the most common type of pathological cyst for women under 30 years of age.
Cystadenomas are ovarian cysts that develop from cells that cover the outer part of the ovary. Some are filled with a thick, mucus-like substance, while others contain a watery liquid.
Rather than growing inside the ovary, cystadenomas are usually attached to the ovary by a stalk. By existing outside the ovary, they can grow quite large. They are rarely cancerous, but they need to be removed surgically.
Cystadenomas are more common among women aged over 40 years.
Signs and symptoms
Most cysts are symptomless. If symptoms are present, they are not always useful for diagnosing an ovarian cyst, because other conditions, such as endometriosis, have similar symptoms.
Symptoms of an ovarian cyst may include:
Irregular and possibly painful menstruation: It may be heavier or lighter than before.
Pain in the pelvis: This may be a persistent pain or an intermittent dull ache that spreads to the lower back and thighs. It may appear just before menstruation begins or ends.
Dyspareunia: This is pelvic pain that occurs during sexual intercourse. Some women might experience pain and discomfort in the abdomen after sex.
Bowel issues: These include pain when passing a stool, pressure on the bowels or a frequent need to pass a stool.
Abdominal issues: There may be bloating, swelling, or heaviness in the abdomen.
Urinary issues: The woman may have problems emptying the bladder fully or she may or feeling the need to urinate frequently.
Hormonal abnormalities: Rarely, the body produces abnormal amounts of hormones, resulting in changes in the way the breasts and body hair grow.