Cysts (Overview)

What Is It?

Cysts are sacs or capsules that form in the skin or inside the body. They may contain fluid or semisolid material. Although cysts can appear anywhere in the body, most frequently they live in the skin, ovaries, breasts or kidneys. Most cysts are not cancerous.

Common locations of cysts include:

  • Skin — Two types of cysts commonly occur underneath the skin, epidermoid cysts and sebaceous cysts. Both usually appear as flesh-colored or whitish-yellow smooth-surfaced lumps. Epidermoid cysts form when surface skin cells move deeper into the skin and multiply. These cells form the wall of the cyst and secrete a soft, yellowish substance called keratin, which fills the cyst. Sebaceous cysts form inside glands that secrete an oily substance called sebum. When normal gland secretions become trapped, they can develop into a pouch filled with a thick, cheese-like substance. Common sites include the back of the neck, the upper back and the scalp.

  • Wrists — Ganglion cysts develop as rubbery or soft swellings, usually in response to a minor injury that triggers excess joint fluid to collect in a saclike structure next to the joint. Ganglion cysts also can occur on the fingers or feet.

  • Knees — A Baker's cyst is a pouch of joint fluid that collects behind the bend of the knee. Because of its location, this cyst may cause the knee joint to feel swollen or tight. In most people, Baker's cysts are linked to arthritis or knee injury.

  • Ovaries — An ovarian follicle that doesn't release its egg may form a cyst on the ovary. These cysts are not harmful and usually disappear after two to three months.

  • Breasts — Breast lumps may be either cystic or solid. Breast cysts are almost always benign (non-cancerous).

  • Vagina — Bartholin's gland cysts may develop in one of the Bartholin's glands, which lie just inside the vaginal canal and produce a protective, lubricating fluid. The buildup of secretions or infections inside one of the Bartholin's glands can cause the gland to swell and form a cyst.

  • Cervix — Nabothian cysts develop when one of the mucous glands of the cervix becomes obstructed.

  • Kidneys — Solitary cysts (also known as simple cysts) are the most common type. They appear as fluid-filled pouches and usually do not cause any symptoms. About 25% of Americans older than age 50 have this type of cyst. Some people inherit the tendency to develop many kidney cysts, a condition called polycystic kidney disease, which often causes high blood pressure and can lead to kidney failure.

Symptoms

Cysts can cause a wide range of symptoms, depending on the type of cyst and its location. Here are some common symptoms grouped by location:

  • Skin — Typically slow growing and painless, skin cysts are usually small, although some can grow to the size of golf balls. They do not cause pain unless they rupture or become inflamed. In these cases, there will be redness, swelling and tenderness.

  • Wrists — Ganglion cysts can appear suddenly and grow quickly. They usually are about the size of a dime, and may be tender to the touch. In some cases, a ganglion cyst may weaken a person's grip or make it painful.

  • Knees — Baker's cyst may feel like a hard-boiled egg when the patient bends the knee. The knee joint may feel swollen and tight. If a cyst breaks open, it can cause pain in the back of the knee or down the leg. If a cyst is large enough, it can lead to swelling in the leg and foot.

  • Ovaries — When ovarian cysts rupture, they cause sudden, severe pain in one side of the lower abdomen or upper pelvis. Ovarian cysts are associated with menstrual spotting and irregular menstruation.

  • Breasts — Most breast cysts do not cause any symptoms. Others are tender to the touch. Cysts may change in size and sensitivity during the course of a menstrual cycle.

  • Vagina — Bartholin's gland cysts may cause a recurring, tender swelling on either side of the vaginal entrance. Sometimes, they can become infected; causing pain, and occasionally pus may drain from them.

  • Cervix — Nabothian cysts usually have no symptoms.

  • Kidneys — Usually, kidney cysts are discovered only when a radiology test is done for another reason. Cysts can sometimes cause back pain. If they grow large enough, they can trigger abdominal pain. Cysts can cause bloody urine. Polycystic kidney disease is an inherited disorder that can lead to kidney failure.

Diagnosis

In cases of visible cysts, such as those in the skin and wrists, your doctor will ask you when you first noticed the cyst, how quickly it grew, whether its size has changed, and if it is painful. During a physical exam, your doctor will look for redness and tenderness and will examine the size and shape of a suspected cyst. Often, this visual inspection is all that's needed.

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