Testicular epidermoid cysts: Sonographic features with histopathologic correlation

Testicular epidermoid cysts are rare, accounting for 1% of all testicular t umors. We present the sonographic appearances of epidermoid cysts in 3 case s, together with the histopathologic correlation. In case 1, sonography sho wed an intratesticular hypoechoic mass with a well-defined echogenic rim; t he mass measured 1.8 x 1.5 x 1.5 cm, and there was no evidence of calcifica tion. In case 2, sonography showed a well-circumscribed mass measuring 1.3 x 1.3 x 1.0 cm, with alternating hypoechoic and hyper-echoic rings (onion-r ing appearance) and no calcifications. In case 3, sonography showed a 2.4- x 2.3- x 2.3-cm, well-circumscribed, oval mass with a heterogeneous echotex ture and an outer hypoechoic halo. The mass contained plaque-like regions o f increased echogenicity, with peripheral acoustic shadowing from refractio n artifact. Hypoechoic clefts were visualized posterior to the plaque-like areas. The triad of findings-sonographic appearance of an onion ring, avasc ularity on Doppler sonography, and negative results of tumor marker studies -is highly suggestive of an epidermoid cyst. (C) 2001 John Wiley & Sons, In c.