CLINICAL CASE 53: Answers and Summary

A 45 Y OLD CAUCASIAN MALE IS SEEN AND YOU DIAGNOSE IDIOPATHIC CALCIUM OXALATE STONE DISEASE. THE STONE FORMATION BEGINS AS SURFACES OF THE RENAL PAPILLAE START COLLECTING SUBUROTHELIAL PLAQUES CALLED RANDALL PLAQUES. WHERE DOES THIS PROCESS BEGIN?

Proximal Tubule  17%
Thin Loop of Henle 30%
Thick Loop of Henle 12%

Distal Collecting Duct 33%

Glomeruli 5%

The correct answer is Thin Loop of Henle.  

http://www.jci.org/articles/view/17038 is the article that made this point with a nice study of biopsies around the plaque sites. They performed intra operative biopsies of plaques in kidneys with calcium stone formers.  They showed this in their paper that the plaques originated in the basement membranes of thin loops of Henle and spread to the interstitum and then the urothelium.  In the patients with obesity related bypass procedures, the stones and plaques were different and instead had intratubular crystals in the collecting ducts.  

The figure 1 and figure 2 from an editorial nicely depicts it.