Xanthogranulomatous pyelonephritis.

To cite: Begum T, Huq ME, Ahmed M. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2016216025 DESCRIPTION A 48-year-old African-American woman was admitted to the hospital, because of weight loss and poor appetite for the past 3 months. The patient mentioned that she had nearly 30 lb of unintentional weight loss during this period. She had neither nausea, vomiting nor chest pain, but had felt mildly feverish with left-sided back and flank pain for the past 2 weeks. The pain was 5/10 in intensity. There was no change in urine frequency, and neither colour change in the urine nor burning on micturition. There was no blood in the urine. The patient mentioned occasional night sweats for the past 2 weeks as well. On two occasions, respectively, she measured her temperature to be 102°F and 101.6° F. At the time of admission, her temperature was 99.6°F and heart rate 120 bpm. Physical examination revealed left-sided costovertebral angle tenderness with an ill-defined mass extending up to the costal margin. Initial white cell count was 22.6×10/mL with 85% neutrophils, and urinalysis was indicative of urine infection. A CT scan of the abdomen and pelvis with intravenous contrast revealed a markedly enlarged left kidney with diminished perfusion. There were multiple lowdensity areas throughout the kidney, suggestive of necrosis or abscess (figures 1 and 2; yellow arrow). There was a little stag horn calculus at the renal pelvis (figure 2; green arrow). There was also perinephric fat stranding with retroperitoneal lymphadenopathy. The diagnosis of xanthogranulomatous pyelonephritis was suggested. A renal biopsy was performed to rule out malignancy, which further confirmed chronic granulomatous inflammatory changes in the renal parenchyma. The patient was started on an intravenous antibiotic with ceftriaxone for initial management. Eventually, she underwent left-sided total nephrectomy.