Images in Clinical Medicine
“Maltese Crosses” in the Nephrotic Syndrome
N Engl J Med 2007; 357:806August 23, 2007
- Article
A 66-year-old man presented with edema, which had developed over the previous month. The urinary sediment showed fatty casts (Panel A), with typical “Maltese crosses” under polarized light (Panel B), and was otherwise unremarkable, with no sign of nephritis. Laboratory evaluation revealed hypoalbuminemia (2.2 g of albumin per deciliter), hypercholesterolemia (369 mg of cholesterol per deciliter [9.5 mmol per liter]), and a serum creatinine level of 1.0 mg per deciliter (88 μmol per liter); a spot urine sample showed a protein-to-creatinine ratio of 13. A diagnosis of idiopathic membranous nephropathy was made on the basis of a renal biopsy and clinical findings. The appearance of Maltese crosses in the sediment is due to the birefringence of the lipid droplets, which consist mainly of cholesterol esters. A finding of this physicochemical phenomenon can prove useful in the diagnosis of the nephrotic syndrome. The patient was treated with prednisone and cyclophosphamide. The proteinuria showed a steady decline, and after 9 months, there was complete remission, with resolution of all laboratory abnormalities. The immunosuppressive medications were tapered and then discontinued, and the patient continues to do well.
Martin Sedlacek, M.D.
Anton C. Schoolwerth, M.D.
Dartmouth–Hitchcock Medical Center, Lebanon, NH 03756-0001
martin.sedlacek@hitchcock. org
