MR imaging of xanthogranulomatous pyelonephritis

Infectious and Inflammatory Diseases of the Urinary Tract: Role of MR Imaging

Urinary tract infection (UTI) is among the most common of bacterial infections. Imaging studies are only required in cases of complicated UTIs. Ultrasound remains the first-line imaging method; however, CT is the gold standard for evaluation of UTIs. MR imaging's improved contrast resolution and absence of ionizing radiation may recommend its use for assessment of lower UTIs. Furthermore, MR imaging performs with diagnostic accuracy at least similar to CT in complicated UTIs, except for the identification of calculi and emphysematous pyelonephritis. In this article, the role of MR imaging for the evaluation of infectious and inflammatory disease processes of the urinary tract is reviewed.

Xanthogranulomatous pyelonephritis in adults: clinical and radiological findings in diffuse and focal forms

AIM

To describe the clinical and radiological features of focal and diffuse xanthogranulomatous pyelonephritis (XGP) in adults.

MATERIALS AND METHODS

A retrospective review of the clinical data, laboratory findings, imaging features, and surgical treatment of 13 cases of histologically proven XGP diagnosed between January 1993 and December 2005 was undertaken. There were 10 women and three men with a mean age of 55.2 years (range 30-87 years). All patients underwent both sonography and computed tomography (CT) of the kidneys. Magnetic resonance imaging (MRI) was performed in two patients.

RESULTS

XGP was diffuse in 11 patients and focal in two patients. Fever, anorexia and weight loss, urinary symptoms, and flank pain were the most common manifestations. Urinary tract infection was found in eight patients. Sonography and CT showed diffuse kidney enlargement in seven cases and atrophy in five cases; a solitary solid mass was found in two patients. Hydronephrosis was noted in nine cases, staghorn calculus in six, and extensive pararenal disease in six. MRI failed to provide the preoperative diagnosis in the two patients with focal XGP. Total or partial nephrectomy was performed without postoperative complications.

CONCLUSION

Although rare, XGP is the main differential diagnosis of malignant renal neoplasia. The definitive diagnosis depends on histological examination of the operative specimen. Preoperatively, the diagnosis can often be suspected based on imaging studies, primarily CT.

MRI and CT features in two unusual cases of xanthogranulomatous pyelonephritis

Two unusual cases of xanthogranulomatous pyelonephritis studied by both magnetic resonance imaging and computed tomography, are presented. Extension of the disease depicted by both computed tomography and magnetic resonance imaging was compatible with the findings at surgery. Computed tomography seems to be sufficient for xanthogranulomatous pyelonephritis imaging evaluation, while magnetic resonance imaging is not recommended on a routine basis, since no additional valuable information is yielded.

Xanthogranulomatous pyelonephritis mimicking malignant disease: is preservation of the kidney possible?

Xanthogranulomatous pyelonephritis (XGP) is an uncommon form of pyelonephritis rarely seen in children. It is characterized by destruction of the renal parenchyma and invasion of adjacent tissues, mimicking renal tumors. Preoperative diagnosis is very difficult. Two children with XGP are presented. One underwent nephrectomy and the other drainage of a renal abscess with kidney preservation. Although surgery is considered the only effective treatment, a high index of suspicion and renal biopsy may prevent radical nephrectomy.

Successful management of bilateral xanthogranulomatous pyelonephritis by bilateral partial nephrectomy

Bilateral xanthogranulomatous pyelonephritis is a rare condition with 7 previously reported cases, all of which required dialysis and/or resulted in death of the patient. We report a case in which bilateral partial nephrectomy was performed successfully for bilateral xanthogranulomatous pyelonephritis. The etiology, symptomatology, radiographic findings and treatment of this rare inflammatory condition are discussed with a brief review of the previously reported cases.

Xanthogranulomatous pyelonephritis: comparison of extent using computed tomography and magnetic resonance imaging in one case

In a case of diffuse xanthogranulomatous pyelonephritis, computed tomography (CT) and magnetic resonance (MR) were used. The MR proved to be more precise in the preoperative evaluation of inflammatory extension to the spleen and into the abdominal wall. The CT was more accurate in excluding spread to the colon.