The hard lumps on the inner thighs have been a bit painful for several years, which may be caused by lipoma, epidermoid cyst or dermatofibroma. 1. Lipoma: a benign tumor formed by proliferation of mature fat cells, more common in middle-aged people, can occur in any part of the body, manifested as one or more small packets under the skin, some people may be accompanied by pain, and should be surgically removed when symptoms. 2. Epidermoid cysts: Epidermoid cysts are well-defined dermal nodules, mostly single, adherent to the skin, but the base can be moved, rupture or secondary infection will be accompanied by pain, and can be surgically removed. 3. Dermatofibroma: Dermatofibroma may be a reactive proliferation of fibroblasts triggered by minor skin injuries. Typical lesions are slow-growing round or ovoid solid nodules with smooth or rough surface, long-term friction or infection can cause pain, usually no treatment, surgical excision and histopathological examination if necessary. There may be other reasons for the hard lumps growing on the inner thighs, so we suggest that you go to the hospital in time for examination and standardized treatment.