Large fibres in urinary calculi--promoters of stone formation.

Large fibres (phi 10-20 microns, length up to 5,000 microns) are sometimes imbedded in urinary calculi. It may be that these fibres can catch sediment particles and promote stone growth. By scanning electron microscopy the morphology of the fibres was studied as well as the relationship of the fibres with crystalline stone components. The reported findings suggest that the fibres are possibly formed in the tubuli as the result of an hitherto unknown defect.