Pediatric Hydrocele Etiology: patent processus vaginalisImaging: simple fluid in the scrotum surrounding the testicle Radiology Cases of Hydrocele Transverse and sagittal US of the right scrotum (above) shows a large anechoic fluid collection around the right testicle and epididymis. Sagittal US of the left scrotum (below) for comparison shows no fluid collection around the normal appearing left testicle. Transverse (above) and sagittal (below) US of the scrotum shows a small amount of anechoic simple fluid around the right testicle and a large amount of anechoic simple fluid around the left testicle. Sagittal US of the left scrotum (above) is unremarkable while sagittal US of the right scrotum (below) shows a large anechoic fluid collection surrounding the right testicle. Axial CT with contrast of the abdomen (above) shows a heterogenous appearance to the enlarged right testicle which is surrounded by an edematous scrotal sac. Sagittal US of the right scrotum (below) again shows the thickened edematous scrotal sac, the heterogenous testicle, and an anechoic fluid collection surrounding the testicle.