Hard lumps in the belly of the leg may be related to dermatofibroma, lipoma, subcutaneous cysts and other causes. 1. Dermatofibroma: it may be caused by skin damage or mosquito bites, due to the proliferation of dermal fibroblasts and the formation of fibroma, manifested as a slow-growing hemispherical nodule, generally asymptomatic, can be manifested as hard lumps in the belly of the leg. 2. Lipoma: generally belongs to benign tumors, refers to the appearance of fat-like tissue between the skin and muscle, good mobility, mostly painless, can also be manifested as hard lumps in the belly of the leg. 3. Subcutaneous cysts: caused by congenital developmental abnormalities or genetic reasons, manifested as round or oval cystic swellings elevated in the skin, slow growth, hard texture, elasticity, good mobility. There are other reasons for the hard lumps in the leg belly, it is recommended that patients go to the regular hospital in time, clear causes, standardized treatment under the guidance of the doctor.