Effect of Kidney Volume on the Results of Nephrectomy Performed for Xanthogranulomatous Pyelonephritis

Xanthogranulomatous pyelonephritis with polycystic kidney disease as a mimic of cystic renal cell carcinoma: a case report

BACKGROUND

Xanthogranulomatous pyelonephritis (XGP) is a rare chronic pyelonephritis that often mimics other renal diseases, when combined with autosomal dominant polycystic kidney disease(ADPKD), preoperative diagnosis is exceedingly difficult. It is important for clinicians to be aware of an XGP with ADPKD since a misdiagnosis can lead to unnecessary surgical intervention.

CASE PRESENTATION

Here, we report a case of a 66-year-old female with a history of bilateral ADPKD and urinary tract infection admitted to our hospital due to right flank pain, feeble, and low-grade fever. Contrast-enhanced ultrasound revealed a malignant mass of the right kidney suspected to be a cystic renal cell carcinoma with polycystic kidney disease. In addition, contrast-enhanced computed tomography (CT) and fluorine 18 fluorodeoxyglucose PET/CT (¹⁸F FDG PET/CT) showed similar results. Subsequently, the patient underwent a right radical nephrectomy, but histopathological examination revealed XGP with ADPKD. On the follow-up, the patient's symptoms were relieved.

CONCLUSIONS

XGP should be kept in mind during the differential diagnosis of renal masses with ADPKD even in the absence of characteristic clinical symptoms and imaging manifestations.

Xanthogranulomatous pyelonephritis: a review and meta-analysis with a focus on management

PURPOSE

Xanthogranulomatous pyelonephritis (XGP) is a rare form of pyelonephritis more commonly seen in females and diabetics. Frequently associated with renal tract calculi, it is often difficult to diagnose, as it can clinically and radiologically mimic other disorders. Most cases are treated with antibiotics and nephrectomy. The aim of our review is to summarise and analyse the current evidence focusing on management.

METHODS

A literature search was conducted to identify papers relating to xanthogranulomatous pyelonephritis in adults. Studies containing ten or more patients with XGP were included for descriptive analysis, and a meta-analyses of cohort studies conducted comparing open and minimally invasive nephrectomy undertaken. Other papers were included for narrative review.

RESULTS

52 studies were identified, 20 were included for narrative review and 32 retrospective observational studies containing 868 patients were included for descriptive analysis. 99.8% of patients underwent nephrectomy, about one-third laparoscopically. The most commonly cultured organisms were Escherichia coli and Proteus mirabilis. 60% of patients, where reported, underwent preoperative drainage. Seven studies containing 211 patients were included for meta-analysis which found that postoperative complications, length of stay and transfusion requirements were all significantly reduced in those who underwent minimally invasive surgery.

CONCLUSION

The mainstay management of XGP is antibiotic therapy and nephrectomy. Some studies highlight a role for preoperative upper urinary tract drainage, but evidence supporting this is limited. We present the first meta-analyses examining operative approach for patients undergoing nephrectomy for XGP. Though limited by the data available, our meta-analysis indicates minimally invasive nephrectomy for XGP provides better postoperative outcomes.

Xanthogranulomatous pyelonephritis: Case series - Clinical, radiologic, therapeutic, and histological aspects

Purpose

Xanthogranulomatous pyelonephritis (XGP) is a chronic and severe infection of the kidney. We aimed to review the main clinical, imaging, and histological findings and to assess predictors of surgical complications or hospitalization >10 days (no deaths reported).

Materials and Methods

We retrospectively searched all patients with XGP treated at our institution from 2005 to 2019, with 57 patients enrolled. Clinical data were retrieved by a single reader, computed tomographic (CT) examinations by two radiologists, and histopathological specimens by an experienced pathologist.

Results

The patients' mean age was 44.3 ± 16.2 years and 41 (71.9%) were female. The most common symptoms were flank/lumbar pain (89.5%), fever (43.9%), and recurrent urinary tract infection (43.9%). The mean time until the presumptive diagnosis was 365.1 days and the median hospitalization period was 11 days. Blood tests showed anemia (78.9%), leukocytosis (43.6%) with left shift (21.6%). Urinalysis showed hematuria (75.6%), bacteriuria (40.9%), and leukocytes (93.2%). Urine cultures showed Escherichia coli in 14.8%, Proteus mirabilis in 7.4%, while 59.3% were negative. Of 40 patients with CT examinations, 38 (95%) presented with hydronephrosis and perinephric inflammatory changes (PIC) and 22 (55%) with Bear Paw sign. PIC was the only independent predictor at multivariate analysis for surgical complications. For prolonged hospitalization, fever and PIC were independent predictors at univariate, but only fever at multivariate analysis.

Conclusions

XGP is a worrisome condition, with unclear pathophysiological mechanisms. Fever and PIC at CT examinations were predictors of poor outcomes.