Xanthogranulomatous Pyelonephritis and Amyloidosis
- 1. Department of Pathology, Hospital of Navarra, España
- 2. Department of Pathology, Hospital del Sureste in Madrid, España
Abstract
The association of systemic amyloidosis and xanthogranulomatous pyelonephritis is extremely uncommon with fourteen cases described in the literature. We present the case of a 68-year-old woman who underwent nephrectomy for an inflammatory mass in her non-functioning left kidney. Histopathological examination of the specimen revealed, in addition to a xanthogranulomatous pyelonephritis, deposits of amyloid in the interstitial blood vessels and in the perirenal adipose tissue. Our purpose is to describe this case, given the unusual association of these entities.
Citation
Areán C, Panizo Á, Álvarez ML, Aguiar B, De Lima G, et al. (2016) Xanthogranulomatous Pyelonephritis and Amyloidosis. Ann Clin Pathol 4(2): 1067.
Keywords
• Pyelonephritis
• Xanthogranulomatous
• Amyloidosis
• Systemic
ABBREVIATIONS
XGP: Xantho Granulomatous Pyelonephritis; AA: Amyloid A; SAA: Serum Amyloid A; CT: Computerized axial Tomography
INTRODUCTION
Xanthogranulomatous pyelonephritis (XGP) is the inflammatory sequel of chronic supurative renal infections and usually develops in an obstructed kidney in which portions of the renal parenchyma are transformed into a xanthomatous and suppurative inflammatory mass [1]. It has a common association with Proteus or Eschericia coli infection, although Pseudomonas species have also been implicated [2]. In the other hand, Amyloid A (AA) amyloidosis is probably the most common type of amyloidosis worldwide and its deposits are composed mainly of the serum amyloid A (SAA) protein (an apolipoprotein of high density that serves as a dynamic acute phase reactant) [3]. It may occur in either sporadic or familial settings, developing in association with an enhanced and prolonged inflammation that leads to a sustained upregulated production of SAA and, subsequently, to incomplete degradation, misfolding, and deposition in the tissues [4]. Both of these entities are relatively frequent pathologies with innumerable cases being reported, however, their association is extremely rare [2].
CASE PRESENTATION
A 68-year-old woman presented with abdominal pain, weight loss and anemia. On computerized axial tomography (CT) the left kidney was enlarged with pyelocalyceal dilation and calcifications. It was consistent with an inflammatory process which extended to the next adipose tissue and affected the wall of the sigmoid colon. Gross pathological examination revealed a 9,5x6x5 cm kidney, weighing 396g. The renal pyramids were filled with a purulent material and one large staghorn calculi.
Several intrarenal abscesses were present. The perirenal fat was involved (Figure 1). Light microscopy revealed extensive xanthogranulomatous inflammation with abundant foamy macrophages, plasma cells and neutrophils (Figure 2). The residual renal parenchyma had some sclerotic glomeruli, atrophic tubules and interstitial fibrosis. The interstitial blood vessels walls and the perinephric fat showed deposits of a homogeneous eosinophilic material suggestive of amyloid, which was Congo red positive (Figure 3). Evaluation of the stained slides under polarized light revealed greenish birefringence and immunohistochemically it was A-amyloid positive. Also, the Congo red-stained slides were examined under fluorescent microscopy and the amyloid deposits showed red fluorescence. Finally, a diagnosis of xanthogranulomatous pyelonephritis with AA amyloidosis was made.After further review of the patient’s clinical history, she had any symptoms suggestive of amyloidosis in any other location.
DISCUSSION
XGP is a severe, chronic renal parenchymal infection characterized by renal suppuration and collecting system obstruction. Although XGP may involve male or female patients at any age, the disease is predominantly encountered in middleaged women. It treatment consists of nephrectomy and antibiotics [5,6]. Secondary AA amyloidosis is a relatively frequent entity in which the renal involvement is almost a rule. Its underlying main causes are chronic inflammatory processes, specially rheumatoid arthritis, tuberculosis, leprosy, osteomyelitis, syphilis, bronchiectasis and decubitus ulcers, among others [2,7]. It may also occur in some tumors as renal cell carcinoma and Hodgkin?s lymphoma [2]. Even though XGP is indeed a chronic inflammatory process, it is not a common underlying cause of AA amyloidosis. On the contrary, the association between XGP and AA amyloidosis is exceptional. To the best of our knowledge, till date there have been fourteen cases reported in the literature. The first case was described by Querfeld et al. in 1986 [8]. Among the cases described so far, this association is more frequent in female adults (M:F ratio, 2.75:1) and spans all age groups (4-76 years). Nephrolithiasis, weight loss and abdominal pain were the most common clinical manifestations (all of them present in our patient) [2,5,7-14]. Our patient did not have any chronic inflammatory conditions or neoplastic processes known to be associated with amyloidosis. She did not have nephrotic syndrome or relevant clinical manifestations related to the amyloidosis either, but she did have mild proteinuria. In the majority of cases previously reported, there was clinical remission of amyloidosis after removal of the renal lesion [2]. We cannot comment on the further course of the renal function as our patient was lost to subsequent follow up.
In conclusion, we have presented this case in order to obtain a better recognition of XGP as an underlying cause of AA amyloidosis. We consider that, although this association of events is not frequent according to the literature, pathologists must remember to look for amyloid deposits whenever a diagnosis of XGP is made, or when persistent proteinuria develops during the follow up of XGP cases.
Table 1:
| CASE | AUTHOR | YEAR | AGE | GENDER |
| 1 | Querfeld et al | 1986 | 8 | Male |
| 2 | Garber et al | 1989 | 61 | Female |
| 3 | Lauzurica et al | 1991 | 38 | Female |
| 4 | Lauzurica et al | 1991 | 67 | Female |
| 5 | Akhtar et al | 1992 | 44 | Male |
| 6 | Noyan et al | 1995 | 6 | Male |
| 7 | Mazuecos et al | 1996 | 51 | Female |
| 8 | I?lek et al | 1998 | 4 | Male |
| 9 | Rivera et al | 1998 | 74 | Female |
| 10 | Almirall et al | 2001 | 70 | Female |
| 11 | Bilbao et al | 2006 | 51 | Female |
| 12 | Val Bernal et al | 2007 | 76 | Female |
| 13 | Val Bernal et al | 2007 | 54 | Female |
| 14 | Punia et al | 2015 | 25 | Female |
| 15 | Areán et al | 2015 | 68 | Female |
ACKNOWLEDGEMENTS
The authors wish to thank to the pathologist assistants of the Pathology Department of the “ComplejoHospitalario de Navarra” for their help with the special techniques performed in this case.
