Hi, thanks for sharing your health concerns with HCM! Hi, If I were your treating Doctor for this case of an immovable, hard, painless thigh lump, I would come up with only two possibilities like an infected sebaceous cyst or a dermatofibroma-like benign tumor of the skin! However, it could be some lymph node, neurofibroma or histiocytoma also but possibly never cancer! Therefore, nothing to worry about this and try not to get infected there! I suggest you to go for an FNAC test of the lump for confirmation and to relieve your concerns! Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing you good health.