Lumps under the skin felt on the legs may be caused by lipoma, dermatofibroma, sebaceous cysts and other diseases. 1. Lipoma: Lipoma is a common benign tumor of the skin. Superficial lipoma can be manifested as single or multiple subcutaneous confined lumps, which can occur in the legs and other parts of the body. The etiology may be related to heredity, chronic inflammation and systemic lipid metabolism abnormality. 2. Dermatofibroma: Dermatofibroma is a kind of benign disease mainly manifested by hard nodules, the etiology of which is not yet clear, which can occur naturally, or may be caused by insect bites and trauma. Mostly seen in the outer limbs, manifested as slow-growing round nodules, touching with the hand can be found with deep tissue adhesion. 3. Sebaceous cysts: Sebaceous cysts are a kind of lesion in which sebum gradually accumulates to form cysts, the etiology of which is related to the blockage of follicular sebaceous gland orifices, which are all present in the skin and are tightly adherent to the skin, and can be touched by hand. If you feel a lump under the skin on your leg, it is recommended to consult a doctor for a clear diagnosis and treatment.