Xanthogranulomatous pyelonephritis (XGP) is a rare form of pyelonephritis associated with repeated infection, chronic inflammation, and obstruction. Various fistulas, including those to the intestine, are a known association with XGP. Here, a 55-year-old woman with a history of multiple previous renal calculi presented with dysuria and back pain. Contrast-enhanced computed tomography (CT) revealed a soft tissue density in her renal pelvis and perirenal space consistent with XGP along with a tract connecting the upper pole of her right kidney to the second portion of the duodenum. This finding was subsequently confirmed during percutaneous nephrostomy placement, stent placement, a small bowel follow-through study, and upper endoscopy. She was diagnosed with XGP with associated renoduodenal fistula, eventually treated by open nephrectomy with fistula takedown. Histopathologic analysis was consistent with the diagnosis of XGP with no malignant or infectious cause of the fistula. XGP should be considered in the diagnosis of patients with dysuria and back pain, especially when a history of obstruction or chronic inflammation. Associated fistulas should also be considered prior to surgical management to prevent complications.
We report the case of a 55-year-old female presenting with dysuria and costovertebral angle tenderness who was found to have right-sided xanthogranulomatous pyelonephritis (XGP) associated with renoduodenal fistula. This finding was confirmed by CT, percutaneous nephrostomy placement, stent placement, small bowel follow-through study, and upper endoscopy. Histological analysis of the small bowel biopsy revealed no malignant or infectious etiology.
A 55-year-old female with a history of recurrent nephrolithiasis was admitted with a 2-month history of progressive fatigue, weight loss, dysuria, and fevers. She had no prior history of urological instrumentation. On examination, she was found to have mild bilateral lower quadrant abdominal tenderness and pronounced costovertebral angle tenderness on the right side. Initial laboratory evaluation revealed pyuria, but no hematuria or leukocytosis. A contrast-enhanced CT of her abdomen and pelvis revealed a soft tissue density in the pelvis and perirenal space along with multiple intrarenal hypodense collections consistent with xanthogranulomatous pyelonephritis. Two small, nonobstructing calculi were identified in the collecting system and the right calyx with associated inflammatory changes. Additionally, a tract extending from the upper pole of the kidney to the second portion of the duodenum was visualized (Figure
CT scan of the abdomen demonstrating a fistula between the upper pole of the right kidney and the duodenum.
During subsequent percutaneous nephrostomy placement, contrast was visualized extending from the renal calyces into the patient’s duodenum and stomach (Figure
Contrast flowing from right renal calix into duodenum and stomach during attempted PCN placement.
Small bowel follow-through study demonstrating contrast flowing from the second stage of the duodenum through a fistula towards the right kidney.
After ureteral stent placement and eight days of treatment with IV ceftriaxone, the patient’s fatigue, dysuria, and costovertebral angle tenderness resolved. A diagnosis of XGP associated with spontaneous renoduodenal fistula and was made, and the patient was discharged in stable condition on oral antibiotics. After discharge, an outpatient open nephrectomy with take-down of the renoduodenal fistula was performed. Gross findings and surgical pathology revealed acute on chronic pyelonephritis with multinucleated giant cells, consistent with XGP.
First described by Schlagenhaufer [
Though rare in the general population, XGP is a relatively common variant found in surgically managed pyelonephritis. In one series, it was found to be the histopathological diagnosis in 20% of such cases [
Though XGP is usually limited to the affected kidney, it occasionally spreads to adjacent tissues. Malek and Elder classified the spread of the disease into the following stages [
Among Stage III disease, fistula formation is known to be associated with XGP, with reports of fistulas forming to the skin, bronchi, psoas muscle, and intestine [
Though XGP remains a rare entity to encounter in clinical practice, it is important to be aware of the possibility, especially in patients with chronic urolithiasis. When XGP does occur, one must be cognizant of the possibility of a fistula prior to surgical management to avoid surgical complications in the patient.
The authors have no conflicts of interest.
The authors would like to thank Dr. Daniel Musher for his valuable advice on this manuscript.