Histopathology and surgical anatomy of patients with primary hyperparathyroidism and calcium phosphate stones

Using a combination of intra-operative digital photography and micro-biopsy we measured renal cortical and papillary changes in five patients with primary hyperparathyroidism and abundant calcium phosphate kidney stones. Major tissue changes were variable papillary flattening and retraction, dilation of the ducts of Bellini, and plugging with apatite deposits of the inner medullary collecting ducts and ducts of Bellini. Some of the papillae in two of the patients contained plentiful large interstitial deposits of Randall's plaque and where the deposits were most plentiful we found overgrowth of the attached stones. Hence, this disease combines features previously described in brushite stone formers-dilation, plugging of ducts and papillary deformity-with the interstitial plaque and stone overgrowth characteristic of routine idiopathic calcium oxalate stone formers, suggesting that these two patterns can coexist in a single patient.