Figure 9a. Choriocarcinoma in a 16-year-old boy who presented with enlarged inguinal lymph nodes. (a, b) Fast SE STIR whole-body MR images, obtained after inguinal lymph node resection, demonstrate a heterogeneous pelvic mass (arrowheads in a), bright lung nodules (arrows in a), and a seroma in the left inguina (arrow in b). The left testis is enlarged and less intense than the right (arrowheads in b), an appearance suggestive of a testicular mass. (c) Contrast-enhanced CT image shows three lung nodules (arrows). (d) Transverse US image of the pelvis demonstrates a solid mass (arrowheads) behind the bladder. (e) Longitudinal US image demonstrates a mixed solid and cystic mass in the left testis (arrowheads).