There is a hard lump between the scrotum and leg which is painless and gradually getting bigger, and the common clinical causes are dermatofibroma, lipoma, sebaceous cysts and so on. 1. Dermatofibroma: this disease refers to a kind of benign tumor in the dermis caused by the proliferation of fibroblasts or histiocytes, and its typical feature is the round or ovoid solid nodule visible to the naked eye in the surface layer of the skin, and the diseased people usually have no conscious symptoms. 2. Lipoma: this kind of tumor can occur in any part of the body where fat exists, which is mainly composed of mature fat cells, and the clinical manifestation is single or multiple limited lumps located under the skin. 3. Sebaceous cysts: this refers to a kind of retention cysts formed when the sebaceous gland ducts in the skin are blocked, resulting in the gradual accumulation of sebum, which grows slowly and usually requires no treatment. The above symptoms may also be caused by other factors. If the condition worsens, it is recommended that you seek medical attention at a regular hospital.