Xanthogranulomatous pyelonephritis: clinical findings and surgical considerations.

OBJECTIVE: Xanthogranulomatous pyelonephritis (XGP) is an uncommon but well-characterized inflammatory process of the kidney. Few reports, however, have correlated preoperative radiographic features with findings at surgical exploration. We report our experience in the surgical management of XGP with emphasis on the use of computed tomography (CT) in the preoperative evaluation.
METHODS: We retrospectively reviewed all medical records including radiographic materials of 27 patients with a pathologic diagnosis of XGP. In particular, preoperative CT features were analyzed to see if they correlated with surgical findings.
RESULTS: A CT scan was performed in 23 of the 27 patients. Of these 23 patients 20 (87%) were diagnosed with XGP based on the CT findings. CT accurately defined the extent of the perinephric inflammatory reaction, identifying 8 patients with muscular extension, 3 with splenic involvement, 1 with extension into the colon, and 5 with encasement of the great vessels. In no case did CT underestimate the involvement of adjacent tissues.
CONCLUSIONS: Although XGP is a rare disease, a careful preoperative evaluation can suggest its diagnosis. CT is particularly valuable in that it not only demonstrates characteristic renal findings, but also shows the extent of inflammation and extent into adjacent tissues. This will aid in surgical planning in choosing an approach that will provide adequate exposure and facilitate patient care.