XANTHOGRANULOMATOUS PYELONEPHRITIS

Analysis of 39 cases of xanthogranulomatous pyelonephritis with emphasis on CT findings

OBJECTIVE

In this retrospective study a review of the clinical, laboratory and radiologic features of 39 cases of xanthogranulomatous pyelonephritis (XGP) is presented. CT characteristics of XGP are analyzed in detail and the relevant literature is reviewed in order to determine the most typical among them.

MATERIAL AND METHODS

Pathologic material from 39 patients suffering from XGP was reviewed in order to confirm the initial diagnosis. Data compiled from the previous history of the patients, clinical, laboratory, urographic and CT findings, preoperative diagnosis, operative findings and postoperative period were analyzed.

RESULTS

Diffuse and focal forms of XGP were recognized in 38 and 1 cases, respectively. Fever, pain in the flank or abdomen, chills and malaise were the commonest symptoms. A non-functioning kidney and/or staghorn calculus were the commonest urographic findings. When available (15 cases), CT revealed multiple fluid-filled cavities in the affected kidney and demonstrated the extension of the disease to the perinephric spaces in all cases. All patients had undergone nephrectomies, which were characterized as difficult in 60% of cases, whereas two patients developed postoperative complications requiring re-exploration.

CONCLUSIONS

Nephrectomy for XGP may be followed by severe complications and appropriate patient preparation and operation planning is of great importance. CT is considered the imaging technique of choice for diagnosing the disease preoperatively and a plethora of CT characteristics have been described to date. Low-density fluid-filled areas within the renal parenchyma and findings indicating perinephric extension should be considered the most typical CT features of XGP.

Sonographic features of xanthogranulomatous pyelonephritis

PURPOSE

The purpose of this study was to describe the various sonographic features of xanthogranulomatous pyelonephritis (XGP).

METHODS

We retrospectively reviewed the CT, sonographic, and medical records of patients diagnosed with XGP from January 1981 to December 1998. Twenty-seven patients for whom XGP was histopathologically confirmed were included in the study. There were 12 men and 15 women, with an age range of 21-86 years (mean, 57 years). All patients had undergone sonography of the kidneys. The renal size, shape, and outline were recorded. The presence of perinephric fluid accumulation, of obstructive uropathy, or of internal echoes in the dilated collecting system and the echotexture of the renal parenchyma were documented.

RESULTS

We categorized the XGP into 4 groups on the basis of the sonographic features: (1) diffuse hydronephrotic, 12 patients (44%); (2) diffuse parenchymal, 9 patients (33%); (3) diffuse contracted, 4 patients (15%); and (4) segmental or focal, 2 patients (7%). A localized perinephric fluid collection was present in 4 patients (15%). The preoperative sonographic diagnoses were pyonephrosis (n = 14, 52%), renal pelvic tumor with possible associated infection (n = 5, 19%), renal parenchymal mass (n = 2, 7%), hydronephrosis (n = 2, 7%), and chronic pyelonephritis with renal atrophy (n = 4, 15%). XGP was considered a possible diagnosis in only 11 patients (41%).

CONCLUSIONS

XGP has no specific sonographic features but is suggested by parenchymal thinning and hydronephrosis, sonographic signs of chronic obstructive uropathy caused by stones; echoes in the dilated collecting system; and a perinephric fluid collection. CT, needle biopsy, or both are recommended to further evaluate and confirm sonographically suspected XGP.

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.

Evolving concepts in the diagnosis of xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a rare inflammatory process of the kidney that results in focal or diffuse renal enlargement and nonexcretion. In the past, XGP often has been misdiagnosed as renal carcinoma. Newer investigative modalities and an increased awareness of XGP should make preoperative diagnosis possible. Thirty-two cases of XGP are presented, with emphasis on recent advances in radiographic approach to diagnosis.

Xanthogranulomatous pyelonephritis

Four patients with xanthogranulomatous pyelonephritis are presented; all patients were male and their symptoms were not urinary but nonspecific. Three of the patients are from a low socioeconomic class and did not have adequate medical services; therefore, we suggest that the disease is underreported.

Xanthogranulomatous pyelonephritis with emphasis on computerized tomography scan. Retrospective study of 20 cases and literature review

The authors reviewed 20 cases of xanthogranulomatous pyelonephritis. An accurate preoperative diagnosis of this disease is difficult because of its clinical and radiologic similarities to various other renal lesions. A resistant urinary tract infection in a patient with a nonfunctioning kidney and a perinephric abscess should lead to the condition being suspected. Although xanthogranulomatous pyelonephritis is mainly a histologic diagnosis, computerized tomography opens new perspectives in the preoperative determination. This could allow less radical surgery in selected cases.

Xanthogranulomatous abscess of a mullerian duct remnant. A rare lesion of the rectum and anus

A rare example of xanthogranulomatous inflammatory mass and abscess of a Mullerian duct remnant involving the anorectal area is reported. A barium enema showed a bilobed precoccygeal mass of moderate size involving the posterior aspect of the distal rectum. Computed tomography (CT) showed two nonfatty, round masses, one of which contained a small central cystic area. The other mass had a homogeneous appearance and was believed to be in the wall of the rectum. The pathologic specimen showed organizing abscesses and a chronic xanthogranulomatous inflammation in tissue compatible with urogenital tissue, presumably a Mullerian duct remnant. This is the first documented report of anorectal xanthogranulomatous abscess in a Mullerian duct remnant with radiologic findings and histopathologic correlation. Though rare, this lesion should be considered in the differential diagnosis of extrinsic and intramural rectal masses seen on barium enema and CT examinations.

Renal carcinoma with staghorn calculus, perinephric abscess, and xanthogranulomatous pyelonephritis in same kidney. Subcutaneous abscess of thigh as initial presentation

A case is reported of the simultaneous occurrence of renal carcinoma with staghorn calculus, perinephric abscess, and xanthogranulomatous pyelonephritis in the same kidney, with subcutaneous abscess of the thigh as the initial presentation. The coexistence of these diseases in the same kidney would seem to be important since they are frequently confused with each other.

The underestimated hazards of xanthogranulomatous pyelonephritis

Twenty-eight cases of xanthogranulomatous pyelonephritis were studied in retrospect and difficulties in diagnosis and treatment are described. Awareness of the entity is the most effective safeguard against over-aggressive resection for this benign condition.

Xanthogranulomatous pyelonephritis: a critical analysis of 26 cases and of the literature

Manifestations of xanthogranulomatous pyelonephritis in 26 patients closely mimicked those of neoplastic and other inflammatory renal parenchymal diseases. Middle-aged or older women were affected most often. Most patients presented with anemia, chronic febrile illness, a painful tender flank mass and recurrent urosepsis. Some features of nephrogenic hepatic dysfunction were present in 13 patients. Bacterial cultures of renal tissue were almost always positive but the spectrum differed considerably from that of the bladder urine. Urographically, a renal mass lesion was encountered in 62% of the patients, nephrolithiasis in 38% and a functionless kidney in 27%. Angiographically, none of the 4 mass lesions studied was distinguished from hypernephroma. Indeed, a correct preoperative diagnosis was made in only 1 instance. There were 3 stages of xanthogranulomatous pyelonephritis recognized. Treatment consisted of nephrectomy for diffuse or advanced stage disease or both (21 patients), excision of the diseased renal segment for localized and low stage disease (2 patients) and renal biopsy (3 patients). Xanthogranulomatous pyelonephritis did not recur but in some patients bacteriuria continued or hypertension developed.

Xanthogranulomatous pyelonephritis masquerading as occult malignancy

Xanthogranulomatous pyelonephritis (XGP) can present with weight loss, anemia, leukemoid reaction, and generalized debility; there may be no signs or symptoms referable to the urinary tract. Confusion between XGP and renal adenocarcinoma is well recognized, but other malignancies can also be simulated. Case histories of patients with proved XGP whose clinical presentations suggested occult malignancies are recorded. Proteus urinary tract infection, calculi, and a nonvisualizing kidney on intravenous pyelogram should suggest the correct diagnosis. The pathology, bacteriology, diagnosis, and treatment are reviewed.

Nephrogenic hepatic dysfunction: secondary to tumefactive xanthogranulomatous pyelonephritis

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