RS3PE syndrome with iliopsoas bursitis distinguished from an iliopsoas abscess using a CT-guided puncture

Abstract

A 55-year-old man was diagnosed with remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome. Contrast-enhanced computed tomography for cancer screening showed a mass with lowdensity centers with an enhanced rim in the left iliopsoas muscle. We suspected an iliopsoas abscess and performed computed-tomography-guided puncture of the mass. Both Gram staining and the culture of the fluid were negative. We diagnosed the patient with RS3PE syndrome with iliopsoas bursitis and administered lowdose corticosteroids without antibiotics. The symptoms, including left hip pain, quickly disappeared following treatment. Clinicians should be aware that iliopsoas bursitis may resemble an iliopsoas abscess. As a result, it is important to make an accurate differential diagnosis.