Presentation
Upper abdominal discomfort, vague constitutional symptoms and reduced renal function.
Patient Data
X-ray demonstrates a large right sided branched calculus which appears fragmented.
CT demonstrates enlargement of the right kidney with multiple large renal calculi and rounded low-density regions associated with the calculus. The left kidney is markedly atrophic.
Single image from the CT with the right kidney outlined. Note how the dilated low-density calyces form an appearance which has been likened to that of the pads of a bear paw.
MRI demonstrates an enlarged right kidney with heterogeneous signal, hydronephrosis and a staghorn calculus.
Case Discussion
Features are consistent with xanthogranulomatous pyelonephritis and pre-existing staghorn calculus.
Case courtesy of Dr Laura Jimenez Juan (CT) and Dr Natalie Yang (MRI)