Paraduodenal mass as initial presentation of burned-out testicular tumour: case report and literature review.

Testicular germ cell tumours (TGCTs) are relatively rare overall and are mainly encountered in young adults and teenagers. The 'burned-out' phenomenon refers to the spontaneous regression of the primary testicular lesion, generally with the presence of a metastatic germ cell tumour. Regressed tumours with retroperitoneal metastasis, as the first manifestation, represent difficult cases prone to misdiagnosis. Burned-out TGCT is a rare but well-recognized entity, with defined clinical features and diagnostic criteria; however, its etiopathogenesis is still not well defined. We present a case of 37-year-old man with a retroperitoneal mass adjacent to the duodenum identified on CT scan. After surgical excision, histopathologic findings evidenced metastatic non-seminomatous GCT. Testicular examination was normal, but a right testis suspicious lesion was found on ultrasound study. Radical right orchidectomy was performed, and histological examination showed complete regression of TGCT. He underwent first-line chemotherapy with complete response and no evidence of recurrence.