Sonographic appearance of epididymal microlithiasis

We report a case of epididymal microlithiasis that was diagnosed sonographically in a 75-year-old man undergoing scrotal sonographic examination to investigate right groin pain associated with an inguinal hernia. The sonographic appearance was that of multiple comet-shaped foci of microcalcification throughout both epididymides, with associated comet-tail artifacts. The testes had normal appearance with no evidence of testicular microlithiasis. The patient subsequently remained well after hernia repair. To our knowledge, epididymal microlithiasis has only previously been reported in a cadaveric study; the authors of that study hypothesized that the condition is caused by aging, with ischemia likely implicated in the pathogenesis. There are many other patterns of extratesticular calcification, including sperm granuloma, hematoma, and chronic epididymitis. We discuss how these differ in appearance from epididymal microlithiasis. Epididymal microlithiasis is a completely separate entity from testicular microlithiasis and should be recognized and dismissed by sonographers and radiologists.