How did a hard bag grow on the back of the head to do

A hard lump on the back of the head may be an abscess on the occipital bone, which is generally obvious. Some patients may misunderstand that it is a serious disease. It may also be a local bone tumor, osteoma, subcutaneous lipoma or swollen lymph nodes, sebaceous cysts, etc. If suddenly show hard pack or gradually show hard pack, to go to public hospital for further examination, it is best to go to neurosurgery clinic for body surface color ultrasound examination, if color ultrasound examination can not be clear, can further head CT and MRI examination; if subcutaneous lipoma, sebaceous cyst in the case of increasing, can consider surgical treatment.