[Diffuse xanthogranulomatous pyelonephritis: clinical, anatomopathologic, and therapeutic features. Report ot 9 cases and review of the literature]

[Abdominal wall skin nodules revealing xanthogranulomatous pylonephritis]

INTRODUCTION

Xanthogranulomatous pyelonephritis is a chronic pyelonephritis characterized by an inflammatory granulomatous reaction that destroys the renal parenchyma. It is an uncommon entity. Diffuse inflammation has the potential to spread to nearby organs, especially the skin.

OBSERVATION

A 73-year-old patient presented with a three-year history of painful and fistulized nodules on the abdominal wall. The results of abdominal computed tomography and magnetic resonance imaging revealed xanthogranulomatous pyelonephritis with extension to the skin, colon, and psoas muscle. The skin lesions were improved by a double antibiotic therapy. The patient was advised to have a radical left nephrectomy, but he refused surgery and was then lost to follow-up.

CONCLUSION

We report an uncommon case of xanthogranulomatous pyelonephritis revealed by cutaneous nodules of the abdominal wall, with an extension toward the skin, the colon and the psoas muscle.

Pyeloduodenal Fistula in Xanthogranulomatous Pyelonephritis: A Series of Two Cases

Xanthogranulomatous inflammation, characterized by destruction and replacement of tissues with chronic inflammatory cells, including foamy histiocytes and hemosiderin-laden macrophages, is uncommon. In patients with xanthogranulomatous pyelonephritis, inflammation may extend from the kidney to the overlying duodenum, creating a pyeloduodenal fistula that further complicates medical and surgical management. We present two cases with recurrent kidney infections who each ultimately received a nephrectomy and repair of their duodenal fistula.

[Xanthogranulomatous pyelonephritis: main imaging features]

Xanthogranulomatous pyelonephritis is a rare form of chronic pyelonephritis, which frequently has a pseudotumoral appearance, as a result of which differential diagnosis with malignant renal neoplasia is difficult, especially as there are no specific signs of this lesion. The aim of this article is to notice the various histological, clinical and radiological characteristics, and the different modalities of diagnostic and treatment of this affection.

[Imaging features of xanthogranulomatous pyelonephritis]

Pseudotumoral xanthogranulomatous pyelonephritis is a rare chronic renal infection. Preoperative diagnosis is difficult because of its non-specific presentation. The purpose of this retrospective review of 8 cases is to assess the value of different imaging techniques in the evaluation of this pathology. Six males and 2 females, aged 29 to 75 years were included. The right kidney was involved in 5 cases and the left kidney was involved in 3 cases. Involvement was upper polar in 2 cases and lower polar in 6 cases. A kidney stone was present in 3 cases. US showed a heterogeneous hypoechoic lesion in 3 cases, a homogeneous hypoechoic lesion in 3 cases, and isoechoic lesion in 1 case and a cystic lesion in 1 case. CT showed a focal solid lesion with peripheral enhancement in 4 cases and a cystic mass with peripheral enhancement in 3 cases. US features are non-specific. CT shows a non-specific renal mass, the presence of obstruction and demonstrates perirenal involvement. Preoperative MRI, not performed in our patient population, demonstrates specific changes in the perirenal fat that suggests the diagnosis. The diagnosis of pseudotumoral xanthogranulomatous pyelonephritis can be suspected on a constellation of clinical and laboratory findings combined with non-specific features on CT and US and specific MRI features of perirenal fat changes. Percutaneous biopsy may be needed in selected cases to confirm diagnosis.