A 27-year-old man was referred for ultrasonographic (US) evaluation of a painless right testicular mass. The mass had been present for 3 years and had recently increased in size. Physical examination revealed no evidence of lymphadenopathy or gynecomastia. Laboratory test results, including levels of the tumor marker serum ␤-human chorionic gonadotropin, were normal. The patient was admitted for surgery. Inguinal orchiectomy was performed, and the postoperative course was uneventful. Imaging FindingsTesticular US revealed a 1.9 ϫ 1.8 ϫ 1.9-cm solid mass within the right testis with concentric rings of hypoechogenicity and hyperechogenicity ("onion ring" appearance). The center of the mass was slightly echogenic. The surrounding parenchyma and the right epididymis were normal (Fig 1). The patient also had a normal chest radiograph. Pathologic EvaluationAt gross examination, the specimen consisted of a testis measuring 4.5 ϫ 2.5 ϫ 2 cm with an attached spermatic cord 8 cm in length. Bisection of the testis revealed a hard white lesion with concentric rings of white-yellow pastelike material within the testicular parenchyma. The lesion was well encapsulated and sharply delineated from the surrounding parenchyma (Fig 2). Figure 1. Longitudinal (a) and transverse (b) US images of the right testis show a well-circumscribed intratesticular mass (cursors) in the lower medial aspect of the testis. The mass contains alternating rings of hyperechogenicity and hypoechogenicity and has a slightly echogenic center. The surrounding testis is normal. RG f Volume 24 • Special Issue Loya et al S243