a 60-year - old patient presented in the outpatient department with chief complaints of hematuria with off and on episode of urine retention . there was history of passage of small stones in urine occasionally for last few days . on ultrasonography he was found to have 35 g prostate with slightly thickened bladder wall with a large stone in the urinary bladder . x - ray kub showed a large radio - opaque shadow in the pelvic region [ figure 1 ] . patient underwent open cystolithotomy and large bladder stone [ figure 2 ] with multiple small stones were retrieved . patient was started on alpha blockers in the immediate postoperative period and foley 's catheter was removed on the eighth postoperative day . at follow - up of three weeks after the surgery the patient was voiding in good stream with minimal post - void residual urine . as the name implies this variety of stone has a characteristic shape resembling a child 's toy [ figure 3 ] . these types of stone are commonly described in the veterinary literature with common occurrence in cattle , cats and dogs . dogs are mostly commonly affected and canine jackstones are usually composed of silica . depicting child toy called jackstone calcium oxalate is the most common component of urinary calculi . calcium oxalate monohydrate calculi are usually smooth and black , whereas stones comprising calcium oxalate dihydrate tend to be irregular and yellow . prostatic diseases , previous lower urinary tract surgery , metabolic abnormalities , upper urinary tract calculi , intravesicular foreign bodies , spinal cord injuries , transplant surgery etc . the presentation of vesical calculi varies from completely asymptomatic to symptoms of suprapubic pain , dysuria , intermittency , frequency , hesitancy , nocturia , and urinary retention . other common signs include terminal gross hematuria and sudden termination of voiding with some degree of associated pain referred to the tip of the penis , scrotum , perineum , back , or hip . the discomfort may be dull or sharp and is often aggravated by sudden movements and exercise . assuming a supine , prone , or lateral head - down position may alleviate the pain initiated by the stone impacting the bladder neck by causing it to roll back into the bladder . in our case the prostate is the likely cause of this stone . enlarged prostate probably restricts the calculus into its eccentric location and contributes to the growth of stone by causing stasis of urine . it is important to recognize the characteristic shape of the jackstones as they are susceptible to lithotripsy . we did not offer lithotripsy as this modality is known to be less efficacious in case of vesical calculus .
jackstone calculi are urinary tract stones that have a specific appearance resembling toy jacks . 
 they are almost always composed of calcium oxalate dihydrate consist of a dense central core and radiating spicules . 
 they are usually light brown with dark patches and are usually described to occur in the urinary bladder and rarely in the upper urinary tract . 
 their appearance on plain radiographs and computed tomography in human patients has been described .