Cysts are benign diseases that can grow on the surface of the body or inside the internal organs of the body. The contents of cysts are called cystic fluid, which can be a clear yellowish cystic fluid, a chocolate-like sticky cystic fluid, or a jelly-like jelly-like cystic fluid. Common cysts include kidney cysts, liver cysts, simple ovarian cysts, ovarian chocolate cysts, sebaceous cysts, dermatomal cysts, bronchogenic cysts, thyroid cysts, lingual duct cysts, mucus cysts, hair root sheath cysts, midline penile cysts, cornu, etc.