A cyst is a closed pocket under the skin filled with some type of fluid or other material. There are a few different kinds.
Epidermoid Cysts
These are one of the most common types of small, noncancerous bumps that grow under the skin. Typically, they are filled with keratin, a protein that makes up the majority of dead skin cells. They can appear on the shoulders as well as the face, neck and trunk.
Epidermoid cysts may appear because of a clogged hair follicle, or be caused by severe acne, for example.
These bumps are usually harmless, but they can become inflamed or infected if not treated properly. A dermatologist may prescribe an antibiotic or remove them in a minor surgery.
Pilar Cysts
Sometimes called trichilemmal cysts or wens, most of these bumps are similar to epidermoid cysts, but they mainly appear on the scalp (although they can sometimes show up on the face, neck, arms, and legs). About 10 percent of the population are affected by these types of cysts, more often occurring among women than men.
Paralabral Cysts
Paralabral cysts, also called ganglion cysts of the shoulder, are small collections of fluid beneath the skin near the shoulder joint. They are brought on by tears in the labrum, a rim of soft tissue or fibrous cartilage that surrounds the socket of a ball-and-socket joint to make it more stable.
While relatively rare, these swellings arise around the socket of the shoulder joint (glenoid) and sometimes around the hip joint. This type of cyst occurs in around 2 to 4 percent of the population and may present more frequently in males, especially those in their thirties or forties.
Unlike other cysts, paralabral cysts can cause pain. To relieve the ache, treatment first involves conservative options like physical therapy and ultrasound-guided aspiration (a procedure directing a needle into a body part to remove fluid or tissue). If those measures fail, a patient may get surgery to drain the cyst and repair a tear if present.
Bone Cysts
Bone cysts are fluid-filled areas in the bone itself, and most develop in the long bones of the arms or legs. They often have no symptoms and go away on their own, but some weaken the bone and increase the risk of fracture.
Typically, bone cysts are treated with a combination of monitoring with regular X-rays, and injections of corticosteroids into the cyst to help it heal. A surgical procedure may be required in serious cases, such as curettage (scraping out the cyst contents) and bone grafting to fill the cavity.
