Ultrasound Appearances of Pediatric Testicular Yolk Sac Tumors: Twenty-one Cases in a Single Institution.

Testicular yolk sac tumors are rare, and analyses of relevant ultrasound (US) findings are limited. We retrospectively reviewed the US features of 21 pathologically verified cases (patients aged 10-64 months). Neoplasms were unilateral and solitary, occupying part (focal) or all (diffuse) of the testis. Focal lesions (14 cases) were usually solid and ovoid, with a homogeneous echo texture or multiple random anechoic spaces, and hypervascular. Diffuse neoplasms had heterogeneous echo textures; most were hypervascular. On spectral Doppler US imaging, 11 cases had a mean peak systolic velocity of 12.9 cm/s and a mean resistive index of 0.54. Ultrasound is a useful tool for imaging pediatric testes when a yolk sac tumor is suspected.