Right renal pelvic calculus mimicking an extrarenal pelvis

Abstract

A 57-year-old man presented with recurrent intermittent colicky right flank pain of 1-year duration. Intravenous urogram (IVU) on two separate occasions suggested a right-sided, extrarenal pelvis. However, when pain became recurrent and persistent, he had a non-contrast computed tomography (CT) examination, which revealed a calculus in the renal pelvis. Diagnosis was missed in the initial imaging modalities because apart from the dilated pelvis, there was no evidence of hydronephrosis or calculus seen, hence a diagnosis of extrarenal pelvis. This case report highlights the superior utility of CT in imaging of suspected urolithiasis, especially when the patient remains symptomatic. Radiologists should be wary, especially in symptomatic patients with features of extrarenal pelvis on IVU.