A hard substance in the scrotum may be the testicle itself, but it is not excluded that the lesion is due to an epididymal nodule, a scrotal mass, or other factors. 1. The testicle itself: usually the head of the epididymis in men will be an inflated bulge above the testicle, which is usually palpable and of a roundish shape. 2. Epididymal nodules: usually due to chronic or acute epididymitis left untreated for a long period of time, resulting in nodular changes in the epididymis, which causes fibrous proliferation of epididymal tissues and produces a large amount of scar tissues, thus resulting in the appearance of a hard substance in the scrotum. 3. Scrotal mass: usually due to the lesion of scrotal contents, scrotal wall lesion edema and other factors lead to the phenomenon of hardness in the scrotal area. Once the patient has hard objects in the scrotum, it may also be related to other diseases, a symptom alone can not determine the specific cause, it is recommended to go to the hospital in time for further examination.