J Korean Soc Med Ultrasound.
2000 Dec;19(4):265-271.
Sonographic Findings of Xanthogranulomatous Pyelonephritis
- Affiliations
-
- 1Department of Diagnostic Radiology, College of Medicine Chungnam National University Hospital.
Abstract
- PURPOSE
To analyze ultrasonographic (US) findings of xanthogranulomatous pyelonephritis (XGP).
MATERIALS AND METHODS
Thirty-five cases of pathologically proven XGP in 32 patients (bilateral in three patients) were analyzed for preoperative US findings. Compared with findings of computed tomography (CT) and pathology, US findings were retrospectively analyzed for the appearance and size of the kidney, extent & pattern of the disease, and presence & characteristics of calculi, by three radiologists who made a consensus.
RESULTS
Of 32 patients, 30 (94%) except two children were older than 27 years, and 25 (78%) were female. The mean age of the patients was 46 (range 3 to 62 years). Of 35 cases in 32 patients, US appearance of the kidney was reniform in all cases, with nephromegaly in 26 (74%) and hydronephrosis 27 (77%). XGP was diffuse in 28 (80%) and focal in 7 (20%). Hypoechoic or anechoic inflammatory lesions of XGP were found on US in 28 cases, but the lesions were not detected on US due to the echo pattern similar to the normal renal parenchyma in two cases and due to marked acoustic shadowing of staghorn calculi in five cases. Acoustic shadowing of renal calculi was minimal due to the dense peripelvic fibrosis in two cases. Of 21 cases with the extrarenal extension of XGP, the extrarenal extension was not definitely detected in five cases (24%) on US. Urinary calculi were detected in 20 (71%) of 28 cases on US. All of the 12 staghorn calculi were detected in US.
CONCLUSION
XGP had variable US findings in addition to the classic ones. Absence of calculi, nephromegaly or diffusibility may be found on US of XGP. In spite of advantages of US, US also had some limitations in the evalu-ation of renal function, extrarenal extension, and renal parenchyma with large staghorn stone. CT and excretory urography may compensate for these US limitations.
