A 78-year-old man presented to the emergency department with 2 weeks of intermittent macroscopic hematuria, as well as recent bladder fullness, urgency, and suprapubic tenderness. His medical history included benign prostatic hypertrophy and recent placement of a Foley catheter in the context of urinary retention. Contrast-enhanced computed tomographic scans of the abdomen and pelvis demonstrated a 2-cm jackstone (image A and image B). The patient underwent continuous bladder irrigation and received appropriate antibiotics for an identified lower urinary tract infection. He subsequently underwent a transurethral resection of the prostate and transurethral cystolitholapaxy, by which the bladder stone was fragmented and removed successfully via irrigation. 

Jackstones are rare bladder stones, or calculi, that are easily recognized by their uniquely spiculated shape and similar appearance to toy jacks, from which the name is derived.¹ Their composition is typically that of a yellow crystalline calcium oxalate dihyrate.² The spiculated shape has been attributed to repetitive abrasions against the bladder wall, which keeps the crystalline layer free from obstructive apatite or adherent mucoprotein, thus allowing a continuous deposition of calcium oxalate primarily at the spikelike projections.³ Because of their loose crystalline lattice structure, jackstones can be easily broken with methods such as lithotripsy.²