[A case of primary psoas abscess with paravesical extension]

We report a case of primary psoas abscess with paravesical extension. A 16-year-old man who had suffered from remittent fever for two months was admitted to our clinic. He had no urological symptoms or walking disturbances, but ultrasonography showed a well-defined echoic mass at the right paravesical space. Computed tomography confirmed this finding, and right psoas muscle appeared to be enlarged with irregular low density areas. Percutaneous drainage for right paravesical abscess was performed, and 15 ml of pus was obtained. The bacterial and fungal culture of the specimen resulted in no growth of any organisms. Six days after percutaneous drainage, he received en bloc resection of right paravesical abscess with segmental resection of bladder wall and peritoneum adherent to it. Furthermore, the affected region of the right psoas muscle was salvaged as highly upward as possible. Surgical specimen disclosed, pathologically, a non-specific granuloma with stellate necrosis. This finding suggested a feature of cat-scratch disease, tularemia, lymphogranuloma venereum and Yersinia infection. We reviewed the related literature on diagnostic images such as CT, ultrasonography and 67Ga scintigraphy. Moreover, bacterial causes and therapy of primary psoas abscess are discussed.