XGC cannot be confidently distinguished from gallbladder carcinoma radiologically
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CT: GB wall may be focally or diffusely thickened
Low-attenuation intramural nodules and bands (corresponding to foamy cell infiltrate and abscesses)
Pericholecystic fluid and inflammatory change ± fistulous tracts, abscesses, contained perforation, etc.
Inflammation can extend to involve adjacent liver and mimic GB cancer with hepatic invasion
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MR: Gallbladder wall thickening (diffuse > focal) with intramural T2 hyperintensity
Discrete intramural nodules appear T2 hyperintense and hypointense on T1WI and T1WI C+
Thickened gallbladder wall and intramural nodules may show signal drop-out on out-of-phase images
Thickened wall often demonstrates delayed enhancement on T1WI C+
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US: Hypoechoic nodules or bands within thickened GB wall
Gallstones, sludge, echogenic intraluminal debris
PATHOLOGY
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Mucosal ulceration or rupture of Rokitansky-Aschoff sinuses → extravasation of bile into GB wall → phagocytosis of bile lipids → inflammation and xanthoma cell formation
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Gallstones always present and may play causative role
CLINICAL ISSUES
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Symptoms most often similar to acute cholecystitis, but can be chronic and mimic malignancy
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More common in females during 6th or 7th decade of life
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Only definitive treatment is cholecystectomy
(Left) Resected GB shows marked wall thickening and an intramural abscess . A portion of the adjacent liver was resected because of the high intraoperative suspicion of GB cancer. Pathology revealed xanthogranulomatous cholecystitis (XGC).
(Right) Axial CECT shows a thickened wall of the gallbladder, especially the fundus , with an indistinct border with the liver. While the appearance was concerning for gallbladder cancer, this was found to be XGC at cholecystectomy.
(Left) Axial CECT of a patient with RUQ pain shows marked irregular GB wall thickening , intramural low attenuation , and several pericholecystic collections . Low-attenuation intramural nodules in XGC are due to either abscesses or xanthogranulomas.
(Right) Axial NECT in a patient with chronic abdominal pain shows a distended, thick-walled gallbladder exhibiting indistinct margins with the liver . While this was worrisome for carcinoma, XGC was confirmed at surgery.
TERMINOLOGY
Abbreviations
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Xanthogranulomatous cholecystitis (XGC)
Synonyms
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Fibroxanthogranulomatous cholecystitis; xanthogranulomatous cholangitis
Definitions
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Rare inflammatory disorder of gallbladder (GB) characterized by accumulation of lipid-laden macrophages and fibrous tissue
IMAGING
General Features
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Best diagnostic clue
GB wall thickening with intramural low-attenuation/hypoechoic nodules or bands corresponding to foamy cell infiltrates or abscesses
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Location
GB wall
Pericholecystic space
Main lobar hepatic fissure
Imaging Recommendations
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Best imaging tool
CECT or MR
CT Findings
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Imaging findings overlap with acute cholecystitis, chronic cholecystitis, and gallbladder carcinoma
GB wall may be focally or diffusely thickened (± loss of normal wall definition)
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GB wall may demonstrate poor enhancement
Low-attenuation intramural nodules and bands corresponding to foamy cell infiltrate and areas of necrosis/abscess
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Intramural nodule may occupy > 60% of wall surface
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Most unique imaging feature for XGC
Pericholecystic fluid, inflammatory change, and induration ± fistulous tracts, abscesses, contained perforation, etc.
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Inflammation can extend to involve adjacent liver (blurring margin between GB and liver), and thus mimic GB cancer with hepatic invasion
Adjacent focal hyperperfusion of liver/transient hepatic attenuation difference (THAD)
Gallstones almost always present but not always visible on CT
Local lymphadenopathy frequent (usually reactive due to inflammation)
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Helpful findings to differentiate XGC from GB carcinoma
More commonly diffuse wall thickening (rather than focal)
Continuous mucosal line of enhancement
Intramural low-attenuation nodules
Absence of hepatic invasion
Absence of biliary dilatation
Presence of 3 findings leads to 83% sensitivity, 100% specificity, and 91% accuracy for differentiation of XGC from GB carcinoma
MR Findings
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Gallbladder wall thickening (diffuse > focal) with intramural T2 hyperintensity
Areas of xanthogranulomatosis are iso- or slightly T2 hyperintense
Related
Diagnostic Imaging_ Gastrointes - Michael P Federle