Toddler with an acutely enlarged and blue right scrotum

US 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.

The diagnosis was a large right hydrocele.