### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
A large lump has developed under my scalp on the back of my head. It itches sometimes but doesn t really hurt . It s been there for two or three weeks now and hasn t gotten any smaller. If anything, I think it s gotten larger. Should I be concerned? Should I have my doctor look at it? Thanks,

### output:

Hello and welcome to Chat Doctor. I am Chat Doctor. I can understand your concerns and I will be answering you . What is your age.?? Are you diabetic or do you have its family history.?? Any history of chronic disease.?? There are lumps anywhere else or not.?? Lump is painful or not .?? Do you have fever . ?? If I were treating you in my clinic I would have palpated that lump to look for its consistency. I would have looked for its mobility under the skin.I would have done skin pinch test to rule out sebaceous cyst or lipoma.according to the information you presented it seems that you have developed a sebaceous cyst. These cysts are most common in hairy areas. These cysts develop due to blockage of the duct of sebaceous glands. Thus the gland is unable to empty its secretion(sebum) and it enlarges with the passage of time. Sebum helps in the lubrication of hair. The diagnostic point of sebaceous cyst is a puncture(hair follicle on the surface of the cyst).the definitive treatment of sebaceous cyst is its surgical excision which is a minor procedure done using local anesthetic such as lidocaine or bupivacaine. You will be able to home right away.2nd on my list would have been a lipoma. Lipoma is freely mobile under the skin and one can pinch skin overlying it. If lipoma is causing problem i.e. cosmetic problem or in your case interfering with you sleep, then it needs surgical excision. It is also a minor procedure.3rd on my list would have been an abscess. Abscess fluctuates when one puts two fingers on it and presses one finger. Mature abscess will need surgical adequate dependent 