Etiology of Painless Scrotal Mass There are several causes (see table Some Causes of a Painless Scrotal Mass) of a painless scrotal mass but the most common include the following: Hydrocele Nonincarcerated inguinal hernia Varicocele (present in up to 20% of adult men) Less common causes include spermatocele, hematocele, fluid overload, and occasionally testicular cancer.