Abstract
INTRODUCTION: Transverse testicular ectopia is a rare anomaly in which both testes descend toward the same side of the hemiscrotum. CASE PRESENTATION: A 35-year-old man presented with right inguinal enlargement. Computed tomography showed a normal testis in the right hemiscrotum and a 58 mm heterogeneous mass in the right inguinal area. No testis was observed in the left hemiscrotum. The vascular structures extended from the right inguinal mass to the left renal vein. Consequently, the left testicular tumor was diagnosed as transverse testicular ectopia, and a left orchiectomy was performed. The histological diagnosis was seminoma stage pT2. Furthermore, left para-aortic lymph node metastasis developed 10 months postoperatively. A complete response was obtained after systemic chemotherapy. CONCLUSION: Awareness of seminomas in transverse testicular ectopia could facilitate appropriate diagnosis and treatment. Furthermore, the location of the lymph node metastasis indicated that the ectopic testis could have originated from the left side.