[Primary retroperitoneal synovial sarcoma revealed by hemorrhagic shock]. / Synovialosarcome rétropéritonéal révélé par un choc hémorragique.

INTRODUCTION: Primary retroperitoneal synovial sarcoma is a rare malignant neoplasm that typically arises in young adults. We report here an unusual presentation of this tumor during hemorrhagic shock and retroperitoneal hematoma. CASE: A 31-year-old man was admitted complaining of acute violent pain of the right lower abdominal quadrant. Physical examination was normal. The computed tomography scan showed a heterogeneous retroperitoneal mass near the iliac bifurcation, with a diameter of 3 cm and spontaneous contrast. The tumor ruptured shortly afterwards and the patient underwent emergency surgery for hemorrhagic shock and retroperitoneal hematoma. No metastases were observed. Although six cycles of doxorubicin and ifosfamide led to initial clinical and tomographic remission, relapse occurred 17 months later. DISCUSSION: Only 20 cases of primary retroperitoneal synovial sarcoma have been described. They are most often discovered following abdominal pain or anemia. Tumor rupture with retroperitoneal hematoma has not previously been reported. Surgical ablation remains the basis for management of this tumor, and survival appears to depend on its quality. Prognosis is poor. Our case is original by the tumor's location and mode of discovery.