Retroperitoneal metastatic germ cell tumor presenting as a psoas abscess: a diagnostic pitfall.

Most testicular neoplasms are germ cell tumors, the vast majority of which represent seminomas. Most seminomas present localized to the testis, whereas nonseminomatous germ cell tumors more often present with lymph node metastases. Psoas abscesses generally arise from a contiguous intra-abdominal or pelvic infectious process, an adjacent focus of osteomyelitis or septic emboli from distant infectious foci. In this study, the case of a 24-year-old man who presented with a right psoas mass presumptively diagnosed as an abscess secondary to fever and leukocytosis is presented. The patient had a history of right testicular seminoma, and normal serum levels of alpha-fetoprotein and human chorionic gonadotropin. Surgical exploration and biopsy demonstrated seminoma metastasis. This case represents an extremely unusual clinical presentation of metastatic germ cell tumor presenting as a psoas abscess. This unique case represents an unusual presentation of a recurrent germ cell tumor mimicking a psoas abscess. Awareness of possible metastatic testicular germ cell neoplasm as a psoas abscess could prevent diagnosis delay before retroperitoneal tumor debulking.