A cyst is an abnormal pocket of fluid, like a blister, that can form in many different areas of the body including the skin, genitals and internal organs. A cyst can vary in size from a tiny sac right up to a heavy bag containing litres of fluid. The common symptom is swelling around the area, but a cyst may or may not be painful. Sometimes, depending on the cause and location, a cyst contains semi-solid or solid material.
The typical treatment for any cyst is removal by surgery and a routine test for cancer, even though most cysts are benign. All unusual lumps need to be investigated by a qualified health professional.