rarely , severe cholecystitis may result in extravasation of bile through rupture of rokitansky - aschoff sinuses or mucosal ulceration causing severe fibrosis and formation of yellow intramural nodules and xanthogranulomatous reaction known as xanthogranulomatous cholecystitis ( xgc ) [ 1 - 4 ] .
although there is a known association between gallbladder cancer and xgc , it is not clearly understood .
computed tomography ( ct ) has recently become the gold standard investigation of choice in acute abdomen because it is quick , noninvasive , and provides a detailed map of the abdomen .
furthermore , the introduction of multislice ct has increased the diagnostic accuracy of intra - abdominal conditions .
however , ct may also detect incidental silent conditions requiring urgent attention such as abdominal aortic aneurysm ( aaa ) .
we herein present a rare case of a patient who presented with signs of acute cholecystitis and gallbladder empyema .
investigations showed evidence of chronic cholecystitis and an incidental large aaa . at surgery , a suspicious small nodule ( not seen on ct ) was excised .
this rare coexistence of pathologies adds a further dimension to the management dilemma of the multidisciplinary team .
a 79-year - old woman presented to the emergency department with a 5-week history of intermittent right upper quadrant and epigastric pain .
her past medical history included hypertension , myocardial infarction 10 years previously , and bilateral knee replacement . on examination , she had tachycardia of 100 beats per minute with no fever .
abdominal examination revealed a tender mass in the right upper quadrant with a pulsatile epigastric mass .
a full blood count and serum biochemistry showed a hemoglobin level of 11.2 g / dl , leukocytosis of 15  10/l , c - reactive protein level of 141 mg / l , and normal renal and liver function tests
. an urgent ct scan of the abdomen showed evidence of severe cholecystitis with a distended , thick - walled gallbladder , suspected gallbladder empyema , and an incidental 7-cm infrarenal aaa ( fig .
1a ) . immediate percutaneous decompression of the gallbladder empyema with a radiologically placed drain revealed 240 ml of pus .
the patient 's condition improved , and she was discharged home . in view of the adjacent aaa ,
the decision of the multidisciplinary team was to carry out open cholecystectomy followed by staged endovascular aneurysm repair . at surgery , the gallbladder was adherent to the surrounding tissue with dense liver , duodenal , and bowel adhesions . a small nodule ( not clearly seen on ct ) was found adjacent to the distended gallbladder .
xgc is a rare form of chronic cholecystitis , accounting for 0.7% to 13.2% of resected gallbladder specimens .
it is thought that chronic inflammation leads to mucosal ulceration and rupture of rokitansky - aschoff sinuses with extravasation of lipids from bile , resulting in a xanthogranulomatous reaction within the gallbladder wall characterized by formation of multiple intramural yellow nodules ( fig .
this inflammatory process is often extensive and may extend to adjacent organs , forming dense adhesions with a large mass of inflammatory tissue surrounding the gallbladder .
the association between xgc and gallbladder cancer has been shown in the literature in small case series and some single case reports .
it is estimated that xgc and gallbladder cancer coexist in up to 12% of cases .
xgc is often mistaken for carcinoma of the gallbladder both macroscopically during surgery and on ct examinations ; thus , radiological differentiation from cancer can be extremely difficult in the presence of severe inflammation .
furthermore , the fact that xgc can be associated with gallbladder cancer makes the differentiation even more difficult . in our patient ,
the clinical presentation suggested a diagnosis of acute cholecystitis and gallbladder empyema , as confirmed on ct ( fig .
therefore , simple cholecystectomy was carried out as planned ; however , advanced gallbladder cancer was discovered during surgery .
this nodule was less than 1 cm in size and was not shown on ct because of the extensive inflammation surrounding the gallbladder .
diagnosis of xgc on ct can be difficult ; however , the presence of cholelithiasis , thickening of the gallbladder wall of > 3 mm , hypodense nodules within the gallbladder wall , and contrast enhancement of the mucosa with a distinctive presence of a hypodense band around the gallbladder are highly suggestive of xgc .
kim et al .   suggested that the hypodense nodules may represent abscesses of xanthogranulomas . in our patient
following percutaneous drainage of the gallbladder empyema , a second ct scan showed that these hypodense areas remained unchanged , confirming that these areas corresponded to the yellow nodules seen macroscopically in the resected specimen ( fig .
laparoscopic cholecystectomy is often associated with conversion to open surgery in 80% of cases . with the increased use of ct as a gold standard imaging modality in abdominal pain ,
more and more incidental pathologies are identified , some of which prompt urgent attention ( e.g. , aaa ) .
the increase in the aging population has led to a rise in the prevalence of aaa coexisting with other nonvascular pathologies .
it is estimated that 3.5% of patients have an aaa coexisting with intra - abdominal nonvascular disease .
the management of concomitant pathology can present a real challenge to the multidisciplinary team , especially with large aneurysms .
it is unclear whether performing simultaneous procedures or a staged approach results in a better outcome . a study by fry and fry   concluded that the risk of simultaneous biliary and aortic procedures may subject the patient to a major risk of graft infection and death .
they suggested that a staged operation can be performed safely if the time between the cholecystectomy and subsequent aortic reconstruction is less than 4 months .
another report by thomas et al .   supports the above findings . according to the above studies ,
the mortality rate due to performance of cholecystectomy in a single operation with aaa repair can reach to 9% .
even when considering a staged procedure , the order of treatment of both pathologies poses a difficult surgical challenge .
 there have been reports of the coexistence of abdominal aortic aneurysm ( aaa ) with intra - abdominal malignancy including gastric , colonic , pancreatic , and renal . 
 we herein report a case of a previously undiagnosed aaa and a presenting complaint consistent with acute cholecystitis . 
 following cholecystectomy , this was noted to be a rare form of chronic cholecystitis : xanthogranulomatous cholecystitis . 
 there is a known possible association of this uncommon condition with gallbladder cancer . 
 the management of concomitant pathologies can present a real challenge to the multidisciplinary team , especially with large aneurysms . 
INTRODUCTION
CASE REPORT
DISCUSSION