Hello. Thanks for asking from HCM. I can understand your concern. The painless bump over skull without recent history of trauma can be due to : Degenerative changes - With age, our bone degenerate and it leads to sclerosis and bone lysis. It can sometime form bony bump. It is asymptomatic, painless and noticed incidentally. Treatment is observation only. Ct head can confirm diagnosis, but it is needed only if there is any kind of doubt. : Bony mass - Sometimes bony lesions like fibrous dysplasia or osteoma can cause bony swelling. The swelling may be mildly painful, hard, immobile, appears as bump like with stretched skin over it, skin free over it. To confirm it, you have to correlate your features and consult doctor. The doctor will feel it and may advise CT head to rule out it. Diagnosis is confirmed by excising it and sending biopsy. Small swelling less than 1cm size may be observed even patient does not want surgery. Both above swellings are benign. : Calcified hepatoma - It usually occurs after trauma. Blood collects in skin layers and then its covering gets calcified. It presents as hard lump, mobile over skull bone, painless or may be mild pain, skin free, with history of trauma. Again CT head is needed for confirmation of diagnosis. Treatment is surgical excision if painful, large size, cosmetically unacceptable. You can correlate your features and reach upto some conclusion. Skull flattening could be age related degeneration or bony changes associated with above mentioned pathology. Hope it will help you. Thanks Take care. Dr Ishu Bishnoi