A Crystallographic Analysis of Prostatic Calculi according to the Location on Transrectal Prostatic Ultrasonography

Roh, Yong Taek; Uh, Hong Sun; Yoo, Tag Keun

Abstract

PURPOSE: We studied the crystallographic component of the prostatic calculi according to the location on the transrectal prostatic ultrasonography to know the mechanism of the formation of the calculus. MATERIALS AND METHODS: From August, 1995 until May, 1997, 33 prostatic calculi from 24 patients(mean age 59 years, mean size 3.1mm) operated on for prostatism were analyzed by polarization microscopy(ZeissR), X-ray diffraction(PW-1720R, Philips) and infrared spectrophotometer(FTIR-205R, Nicolet). Location of calculi was divided two groups under guide of transrectal prostatic ultrasonography; periurethral and periadenoma type. The periurethral type showed hyperechoic density around the prostatic urethra and the periadenoma type showed hyperechoic density between adenoma and false prostatic capsule(peripheral zone). RESULTS: 22 calculi were the periurethral type and 11 were periadenoma type. Thirty stones from 20 periurethral type and 10 periadenoma type consisted two or three of the following calcium phospate, calcium oxalate and tricalcium phospate. These are mixed by the endogenous origin formed from the prostatic fluid and the exogenous origin formed at least in part from urine. Three stones (2 calcium oxalate, 1 uric acid) contained only one compound which participitate from urine. All of 11 calculi of the pericapsular type had an oxalate component. CONCLUSIONS: The calculi around the periadenoma region may be formed from not only endogenous component(calcium apatite stone) but also exogenous component(calcium oxalate) or intraductal precipitation of oxalate component which has never found in the prostatic fluid. These results may suggest the necessity of reevaluation about oxalate component within the prostatic fluid.