A 38-year-old man with diabetes mellitus, pancreatic insufficiency, and dialysis-dependent renal failure associated with heterozygous HNF-1b mutation presented with numerous painful acral lesions. Clinical examination revealed multiple necrotic lesions (Figure 1a). Histology of finger amputates showed extensive oxalate deposits in a fanlike arrangement (Figure 1b), which were birefringent under polarized light. Plasma oxalate levels were repeatedly severely elevated (50–100 mmol/l) and believed to be caused by enteric hyperoxaluria secondary to the patient’s exocrine pancreatic insufficiency. Primary hyperoxalurias type I and II (but not type III) were excluded by percutaneous liver biopsy with AGT and GRHPR enzyme testing. The patient was on intensive hemodialysis six times per week, pancreatic enzyme replacement therapy, and was given vitamin B6 as a dietary supplement. He later received a high-priority renal transplant. At the 2-year follow-up, renal transplant function was stable, blood oxalate levels were within normal levels (o10 mmol/l), and no new necrotic lesions had appeared.