Diffuse echoes within a simple hydrocele: an imaging caveat.

Low-level swirling echoes were noted in scrotal fluid that ultimately proved to be a hydrocele. This sonographic appearance is similar to a hematocele or pyocele and potentially can cause confusion. We evaluated 14 patients with hydroceles and found these swirling echoes in nine. In each of these patients, the echoes were readily apparent with increased gain and were distinguished from artifact by their motion. We analyzed the fluid from one hydrocele and found high protein levels. We propose that protein aggregates account for these echoes. This appearance should not be confused with that resulting from a traumatic or infectious cause.