Generally, a lump in the testicle is often a lesion of the epididymis, which means that there is a swelling in the epididymis. The so-called epididymis is an appendage of the testicle, located outside and above the testicle. There may be several cases of swelling in the epididymis as follows: 1. Chronic epididymitis. Patients often have a history of acute epididymitis, which turns into chronic, with residual lumps in the epididymis. 2. Epididymal cysts. Also known as seminal cysts, there are usually no obvious symptoms and the mass can be palpated on the outer top of the testicle, and ultrasound can assist in the diagnosis. 3. Epididymal tuberculosis. Patients often have manifestations such as tuberculosis, and the vas deferens has typical bead-like changes.4. There may also be a few epididymal tumors. Therefore, if a testicular mass appears, you should go to the urology department of a regular public hospital for further examination and treatment.