Back cysts, common sebaceous cysts, epidermoid cysts, etc., its corresponding in the hospital to see the dermatology, general surgery, etc.. 1. Sebaceous cysts: due to sebaceous gland ducts are blocked, resulting in sebum and other retention of cystic structures, can be manifested as a protruding swelling on the surface of the skin, at this time to consult the dermatology or general surgery. 2. Epidermoid cyst: mostly caused by trauma, it is a kind of cyst formed by ectopic epidermal cell fragments. The cyst is filled with keratin and the base can be moved, then consult dermatology or general surgery. Back cysts, it is recommended to go to the hospital in time, improve the examination, clarify the cause of the disease, under the guidance of the doctor for standardized treatment.