This is a descriptive paper of micro CT scans of tubular mineralisation in 12 nephrectomy specimens. The authors noted that: in the small number of specimens examined, mineralisation started in the outer medulla and appeared to proceed distally along the tubule to the papilla. The classic description of stone formation is, of course, the reverse of this, with Randall’s plaques thought to represent intratubular mineralisation that form the nidus of calcification. It is interesting, but is limited by the small numbers and the nephrectomies were removed for renal cell carcinoma so it may represent altered kidney physiology. Nevertheless, in an area that is poorly understood, it represents an alternative view to the classic one and is sufficiently controversial to merit an immediate letter of rebuttal from Lingeman et al.