Infantile synchronous primary bilateral testicular germ cell tumor: a case report and review of the literature.

Testicular tumors are uncommon in adults, accounting for <1% of all cancers, with testicular germ cell tumors (TGCTs) representing the majority (>95%) of reported cases. Adult and prepubertal TGCTs are fundamentally distinct and the latter is extremely rare, representing 1% of all pediatric solid tumors and having an annual incidence rate of 0.5-2/100,000 boys. Bilateral TGCTs (BTGCTs) account for 0.5-5% of all testicular tumors; the majority are metachronous, while the synchronous account for approximately 0.5-1%. A 16-month-old boy was admitted to our Urology Department with a 2-week history of a painless scrotal mass. Ultrasonography revealed a homogeneous hyperechoic solid mass with rich blood supply in the right testis, and no discernable testicular tissue. A well-delineated heterogeneous echo mass was found within the left testis. Contrast-enhanced computed tomography (CT) scan showed a significantly enhanced mass in the right testis and a mildly enhanced mass in the left testis. Serum alpha-fetoprotein (AFP) was 12,567 ng/mL, while β-human chorionic gonadotrophin (HCG) and total testosterone levels were normal. Accordingly, bilateral testicular tumors were the primary consideration. The patient underwent right radical inguinal orchiectomy with high ligation of the spermatic cord and left testicle-sparing surgery. Final pathology confirmed a pure yolk sac tumor (YST) from the right testis and a cystic mature teratoma from the left. The follow-up ultrasonography showed no recurrence, with serum AFP returned to normal by postoperative day 44. Synchronous primary BTGCT with teratoma and YST respectively can occur coincidently and successfully treated by testicle-sparing surgery.