Xanthogranulomatous pyelonephritis in adults: clinical, biological, radiological and therapeutic main findings in diffuse and focal forms. About 42 cases.

Introduction: Xanthogranulomatous pyelonephritis (XGPN) is a particular form of chronic renal suppuration characterized by the destruction of renal parenchyma and its replacement by a granulomatous tissue containing xanthomatous cells.

Objective: To report and describe the main clinical, biological, radiological and therapeutic aspects of xanthogranulomatous pyelonephritis in adults in focal and diffuse forms.

Methods: This was a monocentric retrospective study involving 42 cases of XGPN operated and histologically confirmed between 2005 and 2015. We included in our study the patients belonging to any age, of both sexes, with a preoperative CT and whose XGPN diagnosis was confirmed histologically. Clinical, biological, bacteriological, radiological data and surgical procedures were collected and analyzed.

Results: The mean age was 50 years (34-79) with a sex ratio of 0.61. The XGPN was diffuse in 88% and focal in 12% of cases. Clinical symptoms were dominated by low back pain (95%), fever (64%) and recurrent urinary tract infections (41%). Urine culture was positive in 67% of cases and Escherichia Coli was the most isolated germ (36%). 64% of patients had inflammatory anemia and 57% of patients had an inflammatory biological syndrome. Ultrasound and CT revealed obstruction of the urinary tract in all cases: a lithiasic cause in 90% of cases and the rest were isolated cases of retroperitoneal fibrosis, abnormal pyelo-ureteral junction, ureteral stenosis and pyelo-ureteric duplicity. A peri-renal abscess and / or psoas was associated in 6 cases (14%). The preoperative diagnosis was often pyonephrosis (50%). Neoplasia was suspected in 4 cases. The treatment consisted in a radical nephrectomy for all patients preceded by drainage of the excretory pathways in 41% of the cases and drainage of a collection in 21% of the cases.

Conclusion: The XGPN is a rare entity whose diagnosis is difficult. This is suspected on a cluster of clinical and biological arguments and can be evoked on the preoperative CT. The kidney cancer is the main differential diagnosis.