Elsevier

Clinical Radiology

Volume 62, Issue 9, September 2007, Pages 884-890
Clinical Radiology

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

https://doi.org/10.1016/j.crad.2007.04.008Get rights and content

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.

Introduction

Xanthogranulomatous pyelonephritis (XGP) is an unusual form of chronic pyelonephritis in which the renal parenchyma is destroyed and replaced by lipid-laden foamy macrophages. It usually affects middle-aged women with a history of recurrent urinary tract infection, diabetes, or kidney stones. The inflammatory process is usually diffuse and can extend beyond the kidney. The rare focal forms may simulate primary renal tumours. The preoperative imaging diagnosis may be difficult. Although the features of XGP on ultrasonography (US), computed tomography (CT), or magnetic resonance imaging (MRI)1, 2 have been described, the findings provided by these three methods used in combination have not been reported. The purpose of this retrospective study was to describe the clinical, US, CT, and MRI findings in 13 patients with histologically documented XGP.

Section snippets

Materials and methods

We identified 13 cases of XGP documented by histopathological examination of nephrectomy specimens at our hospital between January 1993 and December 2005. The patients were 10 female and three male Caucasians with a mean age of 55.2 years (range 30–87 years). One woman was pregnant at the time of the diagnosis. The following data were abstracted from the medical records: symptoms, history, physical findings, laboratory test results, urine culture results, findings at surgery, and histological

Symptoms and signs

In all patients, a single kidney was involved, the right kidney in seven cases and the left kidney in six. Symptom duration ranged from 2 days to 5 years (mean 6.5 months). The most common complaints were fever (n = 9), anorexia with weight loss (n = 9), and flank pain (n = 7). Symptoms suggesting urinary tract infection (urgency, frequency, and dysuria) were reported by five patients. A mass was palpable in the flank in two patients. Pyuria was not a feature. In two patients, there was a fistulous

Discussion

XGP is a rare form of low-grade chronic renal infection characterized by progressive destruction of the renal parenchyma. The cause is unknown. Women are predominantly affected (in a 3:1 ratio), usually in mid-life (50–60 years) and after a long history of recurrent urinary tract infection or urinary stones.3 Involvement of both kidneys is exceedingly rare.4 XGP is diffuse in 90% of cases. Focal XGP can simulate a tumour. Gross examination shows an enlarged kidney with an irregular surface. The

Cited by (87)

  • Xanthogranulomatous pyelonephritis – A diagnostic and therapeutic dilemma

    2023, American Journal of the Medical Sciences
    Citation Excerpt :

    In Stage II, both the nephric and perinephric fatty tissues are involved. It is now often called diffuse disease.8,11-16 In Stage III, the paranephric tissues and organs are additionally involved.

  • Wunderlich Syndrome: Wonder What It Is

    2022, Current Problems in Diagnostic Radiology
    Citation Excerpt :

    Xanthogranulomatous pyelonephritis (XGP), a chronic inflammation of the renal parenchyma thought to be secondary to chronic infection and obstruction is a rare cause of WS with few available case reports.36 The classic imaging appearance of multiple hypoattenuating masses surrounding a large calculus in the renal pelvis mimicking a “bear's paw” (Fig 15) may be obscured in the setting of hemorrhage precluding definitive preoperative diagnosis; diagnosis is often made at nephrectomy.37,38 Angiographic evaluation of spontaneous hemorrhage in a patient undergoing long-term hemodialysis was first described in the radiology literature in 1971, with contrast extravasation demonstrated from 3 different arteries.39

  • A perirenal mass

    2019, Revue de Medecine Interne
View all citing articles on Scopus
View full text