A 26 years old female presented with dull aching flank pain with elevated ESR, C - reactive protein and positive anti nuclear antibody (ANA). Hypo echoic thin strip was noted in bilateral perirenal region without hydronephrosis on ultrasonography. Delayed enhancing perirenal rim of hypo dense soft tissue in bilaterally perinephric space on CT abdomen. Histological diagnosis of retroperitoneal fibrosis was confirmed.
Retroperitoneal fibrosis, Ultrasonography and CT scan.