Staghorn calculi, such as described in the question, are associated with infection by urea-splitting bacteria (notably Proteus species) and are composed of magnesium ammonium phosphate (struvite). They are more common in women than men, and are far more common in patients requiring chronic bladder catheterisation. Calcium-containing stones are typically seen in patients with hypercalciuria without hypercalcemia; one-fifth of patients with this type of stone have hyperuricosuria. Cholesterol is found in gallstones, not kidney stones. Cystine stones are rare; they may be seen in patients with cystinuria, an autosomal recessive disorder of amino acid metabolism. Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 16. Pathology of the Kidney and Bladder. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.