Autori: Cappoli1,2, F. Maellaro1,2, K. Korreshi1,2, F. Tinti1, I. Umbro1, B. Cerbelli4, G. D’Amati4, F. Iafrate4, P. Chirletti5, S. Lai1.2, R. Cianci1, S. Mazzaferro2,3, A.P. Mitterhofer1,2
Affiliazioni: Dipartimento di Medicina Clinica1, Scuola di Specializzazione in Nefrologia e UOC di Nefrologia2, Dipartimento di Scienze Cardiovascolari, Respiratorie, Nefrologiche, Anestesiologiche e Geriatriche3, Dipartimento di Scienze Radiologiche, Oncologiche e Anatomo Patologiche4, Dipartimento di Scienze Chirurgiche5, Sapienza Università di Roma.
Introduction: Xanthogranulomatous pyelonephritis (XGP) is a chronic inflammatory disorder of the kidney. The pathognomonic microscopic feature of XGP is the lipid-laden foamy macrophage. The diagnosis is overall post-nephrectomy, and the differential diagnosis with renal cell cancer is difficult.
Case report: a 50 years old woman was admitted to our Department for anaemia and acute renal failure. Her medical history included LES and APL, for which she was in therapy with azatioprine and steroid. On admission her laboratory findings showed Hb 7.6 g/dL, creatinine 4.7 mg/dl, while the urine sediment revealed 50 to 100 white cells per high-powered field, but a culture was negative for bacteria. A CT scan revealed a necrotic lesion in the right kidney and a large mass in the left kidney with contrast enhancement infiltrating both pancreas and spleen, a pattern highly suggestive of renal cell cancer. Surgeons suggested a surgical approach with bi-nephrectomy, splenectomy and partial pancreasectomy. Nephrologists suggested to perform a renal biopsy which showed lipid-laden foamy macrophage and was diagnostic for XGP. Since the patient presented fever, chills, leucocytosis and, accordingly with the result of the renal biopsy, antibiotic therapy was started. Two weeks later the patient repeated a CT showing a reduction of the size of the lesion.
Discussion: XGP is a rare disease difficult to diagnose due to its similarity with renal cell carcinoma. Although immunosuppression is a predisposing factor to XGP, only one case is described in association with LES. No conservative therapy is established. In our patient, we decided to continue antibiotic therapy and planned a strict follow up of the lesion to avoid nephrectomy if not strictly necessary.