Xanthogranulomatous pyelonephritis and systemic amyloidosis: report of 2 new cases and the natural history of this association

Systemic Amyloid A Amyloidosis Secondary to Xanthogranulomatous Pyelonephritis

The combination of systemic amyloid A (AA) amyloidosis and xanthogranulomatous pyelonephritis (XGP) resulting from a chronic urinary tract infection is extremely rare. We herein report a case of systemic AA amyloidosis secondary to XGP for which clinical remission developed after nephrectomy. To our knowledge, this is the first case report describing the clinical improvement of systemic AA amyloidosis secondary to XGP after nephrectomy in Japan. Clinicians should be aware of this uncommon combination and search for amyloid depositions in cases of XGP.

Xanthogranulomatous Pyelonephritis: A Narrative Review with Current Perspectives on Diagnostic Imaging and Management, Including Interventional Radiology Techniques

Xanthogranulomatous Pyelonephritis (XGP) is a rare, chronic granulomatous inflammatory condition thought to arise secondary to a combination of obstruction, recurrent bacterial infection and an incomplete immune response resulting in focal or diffuse renal destruction. This destruction may be profound with the potential to infiltrate surrounding tissues and viscera. The imaging features of XGP can be ambiguous, mimicking malignancy, tuberculosis (TB) and malakoplakia earning the title of "the great imitator". Computed tomography (CT) is the mainstay of XGP diagnosis and staging, accurately quantifying the stone burden and staging the renal destruction, including the extent of extra-renal spread. Although some cases in children have been successfully treated with antibiotics alone, nephrectomy remains the most common treatment for XGP in adults. The specific management strategy needs to be tailored to individual patients given the potential constellation of renal and extrarenal abnormalities. Although XGP has classically required open nephrectomy, laparoscopic nephrectomy has an increasing role to play arising from the advancement in laparoscopic skills, technique and instruments. Nephron-sparing partial nephrectomy may be considered in the focal form. Interventional radiology techniques most often play a supportive role, eg, in the initial drainage of associated abscesses, but have rarely achieved renal salvage. This narrative review seeks to synthesise the existing literature and summarise the radiological approach and interventional radiology management situated in a clinical context.

Xanthogranulomatous pyelonephritis: A rare case report of a 54 year old female (a potentially fatal infection)

INTRODUCTION AND IMPORTANCE

Xanthogranulomatous pyelonephritis (XPGN) is a rare pathology of the kidneys occurring in 0.6 to 1% of all cases of renal infections, in both men and women. It is characterized by severe inflammation of the renal parenchyma leading to formation of granulomatous tissue containing lipid-laden macrophages. This condition may mimic less aggressive or benign conditions but may worsen or be fatal if not treated aggressively.

CASE PRESENTATION

Our patient is a 54 year old Caucasian female who presented with five days of left flank pain, hematuria, chills, nausea and vomiting. Imaging and biopsy results showed that the patient had XPGN.

CLINICAL DISCUSSION

XPGN is a difficult condition to diagnose as the symptoms are non-specific relative to renal cell carcinoma or other common renal infections. Definitive diagnosis is made with a biopsy; however, clues in various imaging modalities are used to make a tentative diagnosis. It is unclear whether earlier surgical intervention would have improved overall patient outcomes. Currently, a partial or complete nephrectomy is the only effective treatment.

CONCLUSION

Aggressive management including early diagnosis, antibiotics and nephrectomy appears to be critical in preventing progression and complications of XPNG.

[Abdominal mass revealing xanthogranulomatous pyelonephritis in an infant]

Xanthogranulomatous pyelonephritis (XGP) is a chronic pyelonephritis observed in children and exceptionally in infants. Symptomatology is vague and may delay diagnosis and patient's management. Treatment is based on medical therapy but most often on surgery with poor renal prognosis. We report the case of a 15-month old infant with isolated mass in the left flank. He had no fever or alteration of general state and urine cultures were sterile. Radiological evaluation (renal ultrasound, uroscan and renal scintigraphy) highlighted left non-functioning kidney with "hydropyonephrosis" evoking the diagnosis of XGP. The indication for total nephrectomy by lombotomy was posed and definitive anatomo-pathological examination confirmed the diagnosis of diffuse XGP. This observation emphasizes the importance of suspect PXG in patients with renal mass or malformative uropathy with recurrent urinary tract infections whose treatment should be rigorous and codified.

Xanthogranulomatous Pyelonephritis Associated with Systemic Amyloidosis

Xanthogranulomatous pyelonephritis is rarely associated with systemic amyloidosis. To the best of our knowledge, this association has been described in only nine cases, including the present report. Our first patient, a 76-year-old woman, presented with chronic renal failure and xanthogranulomatous pyelonephritis in the right kidney associated with amyloidosis in the same kidney and ipsilateral adrenal. She has been followed up for 44 months and continues to do well with stable renal function and mild proteinuria. Our second patient, a 54-year-old woman, had a 25-year history of recurrent Proteus mirabilis urinary tract infections. She developed anuric chronic renal failure, becoming dependent on dialysis, and xanthogranulomatous pyelonephritis in the left kidney associated with amyloidosis in the same kidney. She died at 8 days postsurgery. The combination of lesions has been described in childhood and in adults presenting with chronic renal failure or nephrotic syndrome. Clinical remission of amyloidosis develops in a majority of the patients after the removal of the renal lesion. From a pathologic point of view our cases underline the importance of careful histologic examination of removed kidneys, even in conditions characterized by extensive destruction of renal tissue. To prevent the association with amyloidosis we emphasize the importance of early diagnosis and treatment of xanthogranulomatous pyelonephritis.

Segmental dilatation of ureter: Report of two cases

Segmental dilatation of ureter is a giant, focal segmental ureteral dilatation producing an elongated and distorted ureter. Two children presented with this condition, one had ipsilateral megacalycosis and contralateral vesicoureteric reflux. The other had duplication of the kidney. The non-functioning lower moiety showed structure of xanthogranulomatous pyelonephritis.

Amiloidosis secundaria a pielonefritis xantogranulomatosa: presentación de un caso y revisión de la literatura

Xanthogranulomatous pyelonephritis (XGP) is a rare entity characterized by the formation of inflammatory renal masses rich in macrophages loaded with lipids. It is usually secondary to repeated urinary infections and urinary obstruction due to stones, which produce slow destruction of the renal parenchyma, requiring nephrectomy. It may sometimes be associated to secondary amyloidosis that leads to the appearance of a nephrotic syndrome. We have conducted a search in the Medline database between the years 1967 and 2003 and we only found 6 cases in adults and 3 cases in pediatric patients with amyloidosis secondary to xanthogranulomatous pyelonephritis. During this same period, there are more than 570 citations that include more than 1,000 patients with isolated XGP, so that we estimate that amyloidosis that complicates a XGP should be less than 1% of all the XGP cases. We present a case of XGP in a 51 year old female patient associated to amyloidosis that initiated with nephrotic syndrome, analyzing the clinical characteristics of the 9 previous cases. We compared their clinical characteristics with those of 51 patients with xanthogranulomatous pyelonephritis without amyloidosis of a large classical series in order to characterize this clinical picture better.

Diffuse xanthogranulomatous pyelonephritis in a child with severe complications

Xanthogranulomatous pyelonephritis is a rare disease in childhood. Because the symptoms and signs are chronic and non-specific, preoperative diagnosis is usually difficult. We report an 8-year-old boy who had an abdominal mass and anemia for more than 6 months. Fever and dyspnea occurred 4 days prior to admission. Ultrasonography revealed an enlarged right kidney with multiple parenchymal hypoechogenic areas, absence of normal parenchymal structures, and perinephric thickening with multiple calcifications. An abdominal computed tomogram demonstrated an irregular, enlarged right kidney with multiple low-density round areas consistent with hydronephrosis and calculi. Diminished excretion of contrast media and a severe perinephric inflammatory reaction were present. Poor right kidney function was demonstrated by Tc99m-diethylenetriamine penta-acetic acid split renal function examination. We diagnosed xanthogranulomatous pyelonephritis preoperatively based on the clinical and radiological features. The child first had drainage of an extrarenal abscess and antibiotic therapy, followed by definitive nephrectomy. The hospital course was complicated with pleural effusion, peritonitis, pelvic abscess, and sepsis. A two-stage nephrectomy requiring less radical resection and decreasing the surgical complications would have been preferable.

Xanthogranulomatous pyelonephritis in childhood

BACKGROUND

Xanthogranulomatous pyelonephritis is a severe, atypical form of chronic renal parenchymal infection accounting for 6/1000 surgically proved cases of chronic pyelonephritis. Its manifestations mimic those of neoplastic and other inflammatory renal parenchymal diseases and, consequently, it is often misdiagnosed preoperatively.

AIM

To examine the relation between clinical history and the results of renal investigations performed in children with xanthogranulomatous pyelonephritis.

METHOD

A retrospective review of 31 cases presenting with the histopathological diagnosis of xanthogranulomatous pyelonephritis between 1963 and 1999.

RESULTS

The mean follow up was 8.2 years. The male:female ratio was 1:1.1. The left kidney was affected in 26 of the 31 patients. The positive findings on examination and investigation at presentation were: fever, 16 children; pyuria, 26 children; positive urine culture, 16 children. A haemoglobin of < 100 g/l was measured in 27 of 31 patients and 15 of 18 patients tested had a raised erythrocyte sedimentation rate of > 20 mm in the first hour. Twenty six children had renal calculi, with a large reduction in the function of the affected kidney on isotope scintigraphy in 27 of the 29 patients tested. Hypertrophy of the contralateral kidney, shown on imaging, was present in 17 of 31 patients.

CONCLUSIONS

Increasing awareness of this condition should lead to the diagnosis being suspected preoperatively.

Xanthogranulomatous pyelonephritis, the gatekeeper's dilemma: a contemporary look at an old problem

OBJECTIVES

To review 12 patients with a clinicopathogenic diagnosis of xanthogranulomatous pyelonephritis (XGP) and to determine if a computed tomography (CT) scan is the imaging procedure of choice for diagnosis.

METHODS

A retrospective review, over the last 12 years, of patients with XGP at our institution.

RESULTS

Nine of 10 patients (90%) who were evaluated by CT scan had the correct diagnosis made prior to nephrectomy. The most common presenting symptoms and signs were flank pain (64%), leukocytosis (73%), and anemia (82%). Seventy-five percent of the patients had a ureteropelvic junction stone or a staghorn stone in the affected kidney at the time of clinical presentation. Proteus was the most common organism cultured.

CONCLUSIONS

After reviewing the clinical features of these 12 patients, we recommended CT scan to evaluate the patient in whom clinical suspicion of XGP is entertained. CT has proven to be the most accurate imaging study to evaluate this disease.