Xanthogranulomatous Pyelonephritis Associated with Crohn’s Disease and Primary Hyperparathyroidism

doi:10.4236/ojneph.2013.33021

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Open Journal of Nephrology, 2013, 3, 117-119

http://dx.doi.org/10.4236/ojneph.2013.33021 Published Online September 2013 (http://www.scirp.org/journal/ojneph)

Xanthogranulomatous Pyelonephritis Associated with

Crohn’s Disease and Primary Hyperparathyroidism

Mekdess Abebe, Wing Mu, Heesuck Suh, Edward P. Nord,

Nand K. Wadhwa*

Division of Nephrology, Department of Medicine, School of Medicine, State University of New York at Stony Brook,

Stony Brook, USA

Email: *[email protected]

Received May 15, 2013; revised June 20, 2013; accepted July 3, 2013

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

We report on a case of unilateral and diffuse xanthogranulomatous pyelonephritis (XGP) associated with Crohn’s dis-

ease and primary hyperparathyroidism (HPT). The patient had undiagnosed primary HPT for at least a year prior to

presentation. The co-existence of Crohn’s disease and primary HPT caused calcium oxalate stone likely by the known

mechanism of hypercalcemia and hyperoxaluria respectively. The patient developed XGP, a rare disease, as a result of

infected calcium oxalate stone which was treated with antibiotics and unilateral nephrectomy. To the best of our

knowledge, this is the first case of XGP associated with Crohn’s disease and primary HPT.

Keywords: Xanthogranulomatous Pyelonephritis; Hyperparath yro idism; Crohn’s; Hypercalcemia

1. Introduction

XGP is a rare, serious, chronic inflammatory disorder of

the kidney and constitutes less than 1% of chronic

pyelonephritis. It is characterized by destruction of renal

parenchyma and its replacement with granulomatous,

abscess and collection of lipid laden macrophage (xan-

thoma cells) [1]. The disease most frequently presents in

middle-aged groups with a predilection for female gender

[2]. XGP shares many characteristics with renal neo-

plasm in terms of its radio logic appearance and its ab ility

to invade adjacent structures. We report a case of uni-

lateral and diffuse XGP due to undiagnosed primary HPT

and Crohn’s disease leading to uni lateral nephrectomy.

2. Case Report

A 46-year-old white woman presented to emergency

department with a two week history of right flank pain

associated with generalized weakness, dizziness, decreas-

ed appetite and weight loss of 50 pounds in the last few

months. She also had shortness of breath at minimal

exertion. She denied any urinary complaint, fever, nausea

or vomiting. Her significant comorbidities included

Crohn’s disease diagnosed in 2009, small bowel obstruc-

tion due to Crohn’s disease related stricture resulting in

laparoscopic small bowel resection in 2010, chronic pan-

creatitis and bilateral kidney stones. Patient was not on

any medication prior to admission. She was an active

smoker but denied alcohol or illegal drug use.

At presentation, the patient was not in any distress.

Blood pressure was 97/53 mmHg, pulse 92 beats/minute

and temperature was 38.3˚C. She had dry oral mucosa.

Abdominal examination showed mildly distended abdo-

men with right costovertebral angle tenderness. No orga-

nomegally was appreciated. The remainder of the physi-

cal examination was within normal limits. Laboratory

evaluation showed white blood cell count of 11.8 × 10³

/mcL, hemoglobin 7.5 g/dL, hematocrit 22.4% and pla-

telet count of 397 × 10³ /mcL. Serum chemistry showed a

sodium of 134 mEq/L (134 mmol/L), potassium 3.8

mEq/L (3.8 mmol/L), chloride 111 mEq/L (111 mmol/L),

bicarbonate 13 mEq/L (13 mmol/L), blood urea nitrogen

60 mg/dL (21.4 mmol/L) , serum creatinine 3.6 mg/dL

(275 µmol/L) (her serum creatinine was 0.8 mg/dL (61

µmol/L) 6 months prior to this admission), ionized cal-

cium 5.4 mg/dL (1.35 mmol/L), total calcium 9.8 mg/dL

(2.45 mmol/L), corrected calcium for albumin 10.8 mg/

dL (2.7 mmol/L), phosphorous 5.2 mg/dL (1.68 mmol/L),

albumin 2.8 mg/dL and total protein 6.1 mg/dL. Liver

function tests were within normal limits. Anti nuclear

antibody was positive at 1:320. Serum protein electro-

p ho re si s (S PEP ), u ri ne protein electrophoresis (UPEP), C3,

*Corresponding author.

M. ABEBE ET AL.

118

C4, antineutrophil cytoplasmic antibodies, Anti ds DNA

antibodies were negative. Urinalysis showed large leuko-

cyte esterase, WBC > 182 and protein 100 mg/dL. Urine

culture was negative.

Intravenous ceftriaxone and ciprofloxacin therapy was

started for presumed pyelonephritis. Patient also received

IV hydration with normal saline and 4 units of packed

RBC. Renal ultrasound and non-co ntrast computed tomo-

graphy (CT) of the abdomen showed multiple hetero-

geneous and solid app earing lobular soft tissue masses at

the periphery of the mid and lower pole of the right

kidney that extends into the peri-renal space which was

suspicious for malignancy (Figure 1). Bilateral kidney

stones were recognized on CT. MRI of the abdomen

demonstrated enlarged right kidney with some increased

parenchymal signal intensity with poorly defined margin

with peri-nephric infection. However, Indium scan

revealed no evidence of pyelonephritis or renal abscess.

Medical therapy with IV hydration and antibiotics, ini-

tially ceftriaxone and ciprofloxacin, later aztreonam for a

total of 4 weeks were administered. In view of her hyper-

calcemia, she was investigated further and was found to

have elevated serum PTH of 390 pg/mL. A sestamebi

scan and an ultrasound of the neck revealed a right

parathyroid adenoma.

Two weeks after admission, because of persistence of

the right renal mass, CT guided percutaneous biopsy was

performed and revealed 43 cc of turbid fluid which was

negative for malignant cells and culture. Further testing

of the right kidney function using furosemide renal scan

demonstrated residual renal function of <10%. Sub-

sequently, due to suspicion of malignancy in the face of

non functioning and possibly infected right kidney,

patient underwent right nephrectomy 5 weeks after ad-

mission. Gross examination showed a peri-nephric fat

adherent to the capsule of the kidney with fat necrosis

and diffuse yellow-red hemorrhagic tissue (Figure 2(A)).

There was also a 2 cm yellow crushable stone at the

distal ureter occupying the entire lumen. Histopatho-

logy revealed acute and moderate chronic inflammation

with focal marked increased interstitial eosinophils and

lipid laden macrophage (xanthoma cells) (Figure 2(B)),

consistent with XGP pyelonephritis. There was also

nephrocalcinosis, both polarizable and non-polarizable.

Chemical analysis of the stone revealed calcium oxalate

stone. Simultaneously right para- thyroidectomy was also

performed for parathyroid adenoma. After six weeks of

hospital stay, her serum creatinine level was stable at 2.1

mg/dl (160 µmol/L) and was discharged in a stable con-

dition.

3. Discussion

We report on a case of XGP associated with Crohn’s

disease and primary HPT which was unrecognized for at

least a year prior to her present presentation. The co-

existence of primary HPT and Crohn’s disease caused

calcium oxalate stone by the known mechanisms of hy-

percalcemia and hyperoxaluria respectively. To the best

of our knowledg e, this is the first case of XGP secondary

to Crohn’s disease and primary HPT which in turn leads

to calcium oxalate stones.

XGP is a rare chronic inflammation of the kidney and

constitutes less than 1% of chronic pyelonephritis. It is

characterized by destruction of renal parenchyma and its

replacement with granulomas, abscesses and collection

of lipid laden macrophages (xanthoma cells) [1-3]. Fe-

males are more affected than males with a ratio of 1:4,

and with a mean age varing from 45 to 55 years [3,4].

Though the exact mechanism of XGP is not clear, a

number of predisposing factors have been implicated.

The two most common predisposing factors are obstruc-

tion and infection of the genitor-urinary system. Calculi

frequently stag horn type may be seen from 47% to

100% of cases. It is also more commonly seen in renal

transplant recipients and diabetics [4,5]. In our patient,

the combination of primary HPT and Crohn’s disease

leading to kidney stone formation and obstruction, in

addition to her gender and age, are the most likely pre-

disposing factors. XGP is commonly associated with

Escherichia coli and Proteus infection; however bacterial

outgrowth from urine culture is not necessary for diag-

nosis, as in our patient [2,4].

The disease process affects the whole of the kidney in

85% (diffuse form). Focal forms are rare (15%). The le-

sion is generally unilateral and can affect either kidney

with equal frequency. Bilateral lesions are rare and are

associated with poor outcome [2,3]. In the present case, a

diffuse and unilateral form of XGP is observed. Symp-

toms are frequently nonspecific and include flank pain,

fever, weight loss, anorexia and malaise. Uncommon

Figure 1. Non-contrast computed tomography of the abdo-

men and pelvis showing solid appearing soft tissue mass at

the periphery of the mid and lower pole of the right kidney

extending into the peri-nephric space (arrow) and renal

stone (arrow head).

M. ABEBE ET AL.

119

Figure 2. (A) Gross kidney specimen: Fat necrosis and

scattered light yellow colored areas (double arrow) with

diffuse yellow-red hemorrhagic tissue in the calyces (arrow).

(B) Hematoxylin and eosin stain, original magnification

×200, of renal biopsy showing lipid laden macrophage

(xanthoma cells) (arrows) and inflammatory cells.

manifestation such as nephro-cutaneous fistula has also

been described [6]. Physical exam may reveal palpable

and tender flank mass. Clinical findings are easily con-

fused with those of renal tumor in terms of its radio-

graphic appearance and its ability to involve adjacent

structures or organs [2,3]. The d efinitive diagn osis of this

entity is achieved only by histopathology examination

which shows the presence of lipid laden macrophage

(xanthoma cells) [3].

Treatment of XGP consists of nephrectomy after the

initial courses of antimicrobial therapy especially in the

diffuse form since it is associated with a complete

destruction of the kidn ey [4]. Cases of focal XGP treated

with antibiotics alon e have also been described [7 ,8]. Our

patient underwent right nephrectomy and was discharged

in a stable condition after 6 weeks of hospital stay and

her discharge serum creatinine was 2.1 mg/dL (186

µmol/L).

In conclusion, XGP associated with Crohn’s disease

and primary HPT leading to calcium oxalate stones high-

lights the importance of early diagnosis of primary HPT

and management of kidney stones, thus preventing from

potentially incu rable renal complications.

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