Closed pockets of tissue anywhere on the body are generally known as cysts. The pockets or cysts usually contain fluid, but may contain pus, blood, teeth, bone or any other body material.
Cysts can occur anywhere on the body but are quite common on the skin. On the skin, cysts commonly occur on the neck, back, face, scalp, and buttocks
Other areas of the body where cysts commonly occur include the wrist, knee, ovary, breast, pancreas, kidneys, etc. cysts vary in size. Cysts may be visible above the skin or may occur underneath the skin. Depending on the size and location, the cysts may have a range of symptoms.
When they are small they may feel like a small bump on the skin. Cysts are usually smooth and do roll underneath the skin. When they are large they can cause pain or they may impinge on nearby nerves or other important structures.
Cysts can occur for a variety of reasons which include infection, foreign bodies or trauma. In all cases, the body's defensive cells build a wall around the infection or foreign body and enclose it. This is done to prevent the spread of infection. When the bacteria in the cysts grow they putrefy and produce pus
The small cysts usually disappear on their own and no treatment is required. Some cysts on the skin are large, cause pain and contain pus. Those which contain pus are best treated by draining them. These cysts are usually drained under some type of anesthesia and most individuals rapidly improve. Some cysts can be aspirated with a small needle (breast cysts)
Other locations of cysts
Wrists: Cysts typically develop on the wrist joint and are known as ganglion cysts. They feel rubbery and soft.
Knees: Cysts are known to occur behind the knee joint and are called Baker's cyst. They are generally painless but may cause mild discomfort in some individuals.
Breast: Cysts in the breast are quite common and generally contain clear fluid. Most cysts in the breast are non cancerous. They are easily identified on ultrasound.
Ovary: Ovaries can contain cysts and the most common are the chocolate covered cysts as in endometriosis or some ovarian cysts may contain teeth, bone or hair (teratomas).
Vagina: Cysts located on the inside of the vagina near the labia are often the cause of pain and can get infected. These are known as Bartholin cysts. The Bartholin gland secretes lubrication for the surrounding vaginal wall.