Xanthogranulomatous inflammatory lesions : a 10-year clinicopathological study in a teaching hospital

Xanthogranulomatous inflammation(XGI) is a form of chronic inflammation that is destructive to the normal tissue of the affected organ and often presenting as tumour like mass. It is characterized by the presence of lipid-laden macrophages (xanthoma cells) admixed with lymphocytes, plasma cells and neutrophils. Multinucleated giant cells may be present1. Multiple organs have been reported to be affected by this type of inflammation, including kidney, gall bladder,appendix, female genital tract ,male genital tract, urinary bladder,stomach, bone,soft tissue etc.,most commonly the kidney followed by the gall bladder2-4. .The exact pathogenesis of XGI remains unclear.Various possible causes such as infection,ineffective antibiotic therapy, irradiation, abnormalities in lipid metabolism and ineffective clearance of bacteria by phagocytes have been suggested5.


Introduction
Xanthogranulomatous inflammation(XGI) is a form of chronic inflammation that is destructive to the normal tissue of the affected organ and often presenting as tumour like mass.It is characterized by the presence of lipid-laden macrophages (xanthoma cells) admixed with lymphocytes, plasma cells and neutrophils.Multinucleated giant cells may be present 1 .Multiple organs have been reported to be affected by this type of inflammation, including kid-

Material and methods
All cases diagnosed as xanthogranulomatous inflammatory lesion by histopathology from the surgically removed specimens received during a period of 10 years from January 2001 to December 2010 in the department of Pathology, Regional Institute of Medical Sciences,Imphal, Manipur were selected for retrospective study.All the relevant available data regarding age, sex, organ of involvement and association with calculi were collected and recorded.All the slides were reviewed.The results were analyzed.This study was approved by local ethical committee.

Results
A total of 98 cases of xanthogranulomatous inflammatory lesion were diagnosed histopathologically out of which gall bladder constituted 81cases(82.65%)followed by appendix in 11cases(11.22%),kidney in 5 cases(5.1%)and 1case(1.02%) in tube.The number of surgically removed specimens of involved organs included 5382 of gall bladder,4298 of appendix,41 of kidney and 24 of tube and tubo-ovarian mass making a total of 9755 and the overall incidence of xanthogranulomatous inflammation being 1%.(Table 1).The female to male sex ratio was 2.5 : 1.The maximum number of cases were in the age group of 41-50 years with 33.67% followed by 29.59% in the age group of 31-40 years.(Table 2).86.6% cases were associated calculi in gall bladder and 90.2% in kidney.One case was associated with adenocarcinoma of gall bladder.Table 1.

Xanthogranulomatous inflammation
Xantho.Inflam.: Xanthogranulomatous inflamma-tion, TO mass: Tubo-ovarian mass ) could be because of more number of cholecystectomy specimens received in our hospital and a higher incidence of cholelithiasis in the region.(Fig.1).
In a study of xanthogranulomatous pyelonephritis(XGP), 83% were associated with calculi 10 , as compared to 90.2% in the present study.Moreover XGP constituted 5.1% of the total XGI(5/98) but the incidence was highest with 12.19% (5/41) of the total nephrectomy specimens in our study.(Fig.2).100% association with calculi has also been reported in a series of 63 patients of XGP likely a sequel of tubo-ovarian abscess 12 .A case of XGI in fallopian tube in our study was clinically diagnosed as hydrosalpinx.In our study , four cases of cholecystectomy and three cases of nephrectomy specimens were suspected of malignancy clinically, out of which only one turned out to be adenocarcinoma of gall bladder.The aetiopathogenesis of XGI is still debated.Some reports have suggested that it is probably initiated by an obstructive and/ or an ischaemic process leading to infection and tissue necrosis followed by release of cholesterol and other lipids and phagocytosis by macrophages , from the studies of XGI of the genital tract, kidney and gall bladder.A combination of factors may be responsible in some cases 13 .
Guo and Greenson 14 compared histopathology of all interval appendicectomy specimens with a control group of patients who had acute appendicitis and underwent appendicectomy, 36.4% of the interval appendicectomy cases had XGI compared to none in the acute appendicitis group (p<0.0001).Of the 11 cases of XGI in the present study, 8 cases had clinical evidence of acute appendicitis and the rest were of interval(delayed) appendicectomy cases.The incidence in appendix was lowest with 0.25% of the total appendicectomy specimens in the present series.
In the ultrastructural study of the cellular components ,the lipid droplets were also seen in cells other than histiocytes,suggesting that these changes are secondary to a common mechanism comprising factors such as obstruction, haemorrhage, inflammation and local hypoxia 15 .

Conclusion
Although xanthogranulomatous inflammation is benign, it mimics malignancy clinically and morphologically.It is increasingly described in various anatomic locations.A few cases have been found to be associated with malignancy.So meticulous histopathological examination is necessary to rule out malignancy and correct diagnosis will prevent the patients from undergoing aggressive treatment.This benign diagnosis will relieve the psychological panic of patients and clinicians.