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1.History of painless lump at the hairline, most possible cause could be congenital cause,
Cyst.
2.The next possible cause could be
lipoma - fat content. Lastly hair follicular infection - but generally seen with pain.
3.In this case i would recommend
ultrasound examination of the lump - that will help to evaluate the nature of the lesion - cystic, solid, mixed. Its source and extensions. Vascularity status.
4.After that if there is any involvement of spine an
MRI might be necessary - as it will help to evaluate if there is any spinal involvement.
5.I would recommend to o see your GP, let it get examined and you will be sent to scan and further evaluation.
Good luck.
Hope i have answered your query,
any thing to ask ? do not hesitate to ask.
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