In most normal patients, a small amount of fluid (1 to 2 mL) can be seen within the leaves of the tunica vaginalis. Hydrocele is present when an excessive amount of fluid is present. Hydrocele is the most common cause of painless scrotal swelling and may develop secondary to trauma, infection, testicular torsion, or tumor. Idiopathic hydroceles also occur. Congenital hydrocele results from a patent processus vaginalis that allows ascites to enter the scrotal sac. When the fluid contains high protein or cholesterol content, the hydrocele may appear complex or septated. Hematoceles and pyoceles are rare and are usually caused by trauma, surgery, or neoplasm. Pyocele from untreated infection or rupture of abscess typically shows internal septations and loculations on US (Figure 8). Skin thickening and calcifications may also be present.
Appl Radiol. 2006;35(3):8-17. © 2006 Anderson Publishing, Ltd.