Epididymal cysts are formed due to the dilation of the efferent ductules and localized blockage of the epididymal duct, and they typically have characteristic appearances on ultrasound, showing as single or multiple anechoic areas. Epididymal cysts are usually located within the head of the epididymis and appear round or oval in shape with clear boundaries, varying in size from a few millimeters to several centimeters. The cyst walls are thin, with good internal sound transmission, and there are generally no significant blood flow signals inside the cysts. Some parts of the cyst walls may calcify, appearing as strong echoic shadows. Epididymal cysts are a type of benign lesion.