A unilateral epididymal head nodule of 5 cm unchanged for 4 years may be due to a calcified nodule, an inflammatory nodule, or an epididymal cyst. 1. Calcified nodule: It indicates that there was inflammation before, and if it remains untreated, it will leave a calcified focus, and the nodule will be found through examination. Calcified nodules may persist and not go away, and usually do not increase in size. 2. Inflammatory nodules: mainly refers to the possibility of currently having epididymitis, if the condition is relatively stable, the nodules may not increase in size or become smaller. 3. Epididymal cyst: it is a benign tumor that grows slowly, so the cyst may remain for about 4 years, not disappear, and not get bigger. For unilateral epididymal nodule 5 cm cyst, 4 years without change, in addition to the above reasons, but also to consider is due to malignant tumors. At present, it is necessary to go to the hospital in time for review to know whether there is any change in the nodule, and if necessary, it is necessary to carry out pathological biopsy to exclude malignant lesions.