Hi and welocme to hCM.
Most common such lesions are benign epididimal cysts or vein enlargements. This is found oftenly in young men and shouldnt be treated. But you should be aware and follow its size. If become panful,inflammated or continue growing , you should visit urologist
and thne it can be eaisly surgically managed. But probably it will stay as it is and wont need any treatment. Possibiltiy of cancer is minor but as I said the first sign would be rapid enlargement. Wish you good health.