Jackstone in the Kidney: An Unusual Calculus.

Jackstones are stones in the urinary tract that have the characteristic appearance resembling six-pointed toy jacks. They are nearly always reported to occur in the urinary bladder, and the occurrence in less capacious renal pelvis is unusual. We report a solitary, typical jackstone in the renal pelvis without significant outflow obstruction that was successfully treated with retrograde intrarenal surgery followed by extracorporeal shockwave lithotripsy. This highlights the complex pathophysiological mechanisms in stone formation which needs to be further studied. It is important to recognize the characteristic shape of the renal calculi on the radiological investigation in the diagnosis of the jackstones.