Hello and welcome to Healthcare Magic. Thanks for your query.
The soft, 'fatty' lump on your your thigh is most likely a "Lipoma". A Lipoma is a benign (i.e. harmless) tumour which is composed of fatty tissue. They are fairly common and are found in about 1% of people. They are usually small, but sometimes can grow large in size.
Treatment is usually not required, unless it causes pain or restriction of movement. Some people chose to have it removed for cosmetic reasons. The definitive treatment for lipomas
is surgical removal. The procedure is quite simple and can be done as out-patient / day- care basis, under a local anaesthetic
itself. Since lipomas are found just beneath the skin, removal is easy and the whole procedure takes only about 30 minutes.
So, I don't think you have to worry about this. If you have significant discomfort or want to get rid of it due to cosmetic reasons, then the only option would be surgical removal.
Dr. Sheeba Stephen