title: Raman spectroscopic analysis identifies testicular microlithiasis as intratubular hydroxyapatite.
abstract: OBJECTIVE
  As diagnosed by ultrasonography, testicular microlithiasis is associated with various benign and malignant conditions. The molecular constitution of these microliths is largely unknown. Raman spectroscopy provides detailed in situ information about the molecular composition of tissues and to our knowledge it has not been applied to gonadal microliths. We analyzed the molecular composition of gonadal microlithiasis and its surrounding region using Raman spectroscopy in malignant and benign conditions.
  
  
  METHODS
  Multiple microliths from 6 independent samples diagnosed with gonadal microlithiasis by ultrasound and histologically confirmed were investigated by Raman spectroscopy. The samples included 4 testicular parenchyma samples adjacent to a germ cell tumor (4 seminomas), a gonadoblastoma of a dysgenetic gonad and testicular biopsy of a subfertile male without malignancy.
  
  
  RESULTS
  Raman spectroscopic mapping demonstrated that testicular microliths were located within the seminiferous tubule. Glycogen surrounded all microliths in the samples associated with germ cell neoplasm but not in the benign case. The molecular composition of the 26 microliths in all 6 conditions was pure hydroxyapatite.
  
  
  CONCLUSIONS
  Microliths in the testis are located in the seminiferous tubules and composed of hydroxyapatite. In cases of germ cell neoplasm they co-localize with glycogen deposits.
authors.affiliation: Department of Pediatric Urology, Erasmus Medical Center, University Medical Center, Rotterdam, The Netherlands. b.dejong@erasmusmc.nl
authors.forename: B W D
authors.initials: BW
authors.lastname: De Jong
authors.forename: C A
authors.initials: CA
authors.lastname: De Gouveia Brazao
authors.forename: H
authors.initials: H
authors.lastname: Stoop
authors.forename: K P
authors.initials: KP
authors.lastname: Wolffenbuttel
authors.forename: J W
authors.initials: JW
authors.lastname: Oosterhuis
authors.forename: G J
authors.initials: GJ
authors.lastname: Puppels
authors.forename: R F A
authors.initials: RF
authors.lastname: Weber
authors.forename: L H J
authors.initials: LH
authors.lastname: Looijenga
authors.forename: D J
authors.initials: DJ
authors.lastname: Kok
mesh_terms: D002137:Calculi / Q000737:chemistry* / Q000175:diagnosis; D017886:Durapatite / Q000032:analysis*; D006801:Humans; D008297:Male; D013059:Spectrum Analysis, Raman; D013733:Testicular Diseases / Q000175:diagnosis*
chemical_list: D017886:Durapatite