Biopathological crystallization: a general view about the mechanisms of renal stone formation.

A general classification of most common renal calculi (calcium oxalate, phosphate and uric acid stones) based on their formation mechanism is presented. The main etiological factors that enable their development are discussed considering present knowledge of calcium oxalate, insoluble urinary phosphates and uric acid crystallization and the fine structure of respective renal stones. Considering the formation mechanisms of the discussed calculi, common aspects permit us to distinguish two general mechanisms of calculi formation: development of calculi attached to papillary epithelium and development of calculi in cavities without any attachment to urothelium.