If there is a small lump on the surface of the testicle, then the possible causes: First, testicular inflammation: when testicular inflammation or testicular surface can appear unsmooth surface roughness, or hard nodular changes. The acute phase can be accompanied by swelling with pain. In the chronic phase there is no pain, but hard nodules can appear. Most of them are scar nodules caused by the proliferation and repair of fibrous scar tissue after the inflammation has healed. Secondly, testicular tumor: hard nodules may appear in the testis, and the scope may gradually expand. If the nodules are diffuse to the whole testicle, the volume of the testicle increases and the texture becomes hard with the painful feeling of falling, CT examination of the testicle and testicular oncology index examination are needed to further determine; third, epididymal nodules: the epididymis is closely attached to the testicle at the head and tail, and it is often difficult to distinguish the testicle from the head or tail nodules. It can be seen in epididymitis or epididymal cyst, which needs ultrasound examination for further differentiation.