Oxalate deposition in tissues

Keywords: granulomatous reaction; oxalate deposi-tion; oxalosis; primary hyperoxaluria type I; renalosteodystrophyAn 11-year-old boy was found to have primaryhyperoxaluria type I (urine oxalate 828mg/l, N140–420mg/l). His mother had kidney stones and theparents were second degree relatives. After 18 monthsof dialysis, femoral neck fracture occurred, whichwas assumed to be related to renal osteodystrophy.During the surgical procedure to x the fracture siteinternally, biopsies were taken which showed brosisand histiocytic reaction with multinucleated foreignbody macrophages (Figure 1). Under polarized lightmicroscopy birefringent oxalate crystals were detected(Figure 2).In oxalosis, oxalate deposits are mainly found in theheart and in smooth muscle cells of vessels and otherorgans [1,2]. Bone involvement in our patient pre-sumably started in the rich vascular network ofthe bone marrow and nally, with a component ofrenal osteodystrophy, led to a pathological fracture.Severe oxalate bone disease appears to be the