title: The composition and structure of stones in enlarged prostatic utricles (EPU).
abstract: Our objective was to comprehensively test the composition, morphology, and  structure of enlarged prostatic utricle (EPU) stones, which, as a kind of  biolite in abnormal anatomical structures of the genitourinary system, have  not yet been reported. Thirty-one EPU stones coming from 8 patients, who had  been treated in our center from 1985 to 2009, were taken out by transurethral  fenestration of EPU and were analyzed by scanning electron microscopy, x-ray  diffraction (XRD) analysis, and Fourier transformation infrared spectral  (FTIS) analysis. Under scanning electron microscope, all these EPU calculi  were seen to be constituted of many intensive minicrystals and amorphous  matrix. By XRD and FTIS analysis, we determined that the 31 EPU stones in our  research were all hydroxyapatite crystal. We consider that EPU calculi should  belong to the category of prostatic pseudocalculi and that the formation of  EPU calculi is not caused by the abnormal change of urine composition, but  should be ascribed to continuously concentrated EPU liquid by absorption of  capsule walls and calculous matrix mainly coming from deciduous epithelial  cells of EPUs. The role of the amorphous matrix is to link microcrystals,  which promotes the growth of EPU stones.
authors.affiliation: Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Ning-Hong
authors.initials: NH
authors.lastname: Song
authors.forename: Hong-Fei
authors.initials: HF
authors.lastname: Wu
authors.forename: Nai-Cen
authors.initials: NC
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
mesh_terms: D006801:Humans; D008297:Male; D011467:Prostate / Q000473:pathology*; D011469:Prostatic Diseases / Q000473:pathology*; D014961:X-Ray Diffraction