Following vasectomy, spermatogenesis continues, the human epididymis and ductus deferens may distend and leak, and the extravasated spermatozoa stimulate formation of a sperm granuloma. Granulomas may occur at 60% of vasectomy sites and are usually asymptomatic and relieve intraluminal pressure. About 3-5% of patients experience pain. Intraluminal phagocytosis may explain why some reproductive tracts become depleted of spermatozoa. Distension of the epididymis is common after vasectomy and may lead to granuloma formation there. Up to 6% of patients have symptoms, but many with epididymal changes have no discomfort. Most episodes of painful epididymitis and granulomas resolve with conservative treatment, but < 1% require vasectomy reversal or, if this is ineffective, excision of the epididymis and obstructed ductus deferens.