LAUSR

A 79-year-old woman presented to acute services with a 2-week history of shortness of breath, fever and a cough productive of purulent sputum. She had a medical history of polymyalgia rheumatica, chronic obstructive pulmonary disease and hypertension. She had been admitted with a right-sided pleural empyema 9 months earlier, which had been treated with chest tube drainage and intravenous antibiotics. On that occasion, pH of pleural fluid was 6.7, white cell count (WCC) ++, lactate dehydrogenase (LDH) 7554 U/L and total protein 39 g/L (serum total protein 73). Neither pleural fluid nor contemporaneous blood cultures had shown any significant growth. In the past year, she had been found to have right-sided hydronephrosis with contrast-enhanced abdominal CT demonstrating a mass arising from the upper pole of the right kidney. Subsequent percutaneous-guided biopsy performed under the urology team identified prominent collections of foamy histiocytes, with immunohistochemical analysis demonstrating strongly positive staining for CD68 and vimentin. These findings were consistent with a diagnosis of xanthogranulomatous pyelonephritis, thought likely to be secondary to …