Xanthogranulomatous Cholecystitis

 XGC cannot be confidently distinguished from gallbladder carcinoma radiologically



• CT: GB wall may be focally or diffusely thickened 
image Low-attenuation intramural nodules and bands (corresponding to foamy cell infiltrate and abscesses)

image Pericholecystic fluid and inflammatory change ± fistulous tracts, abscesses, contained perforation, etc.

image Inflammation can extend to involve adjacent liver and mimic GB cancer with hepatic invasion

• MR: Gallbladder wall thickening (diffuse > focal) with intramural T2 hyperintensity
image Discrete intramural nodules appear T2 hyperintense and hypointense on T1WI and T1WI C+

image Thickened gallbladder wall and intramural nodules may show signal drop-out on out-of-phase images

image Thickened wall often demonstrates delayed enhancement on T1WI C+

• US: Hypoechoic nodules or bands within thickened GB wall
image Gallstones, sludge, echogenic intraluminal debris




PATHOLOGY




• Mucosal ulceration or rupture of Rokitansky-Aschoff sinuses → extravasation of bile into GB wall → phagocytosis of bile lipids → inflammation and xanthoma cell formation

• Gallstones always present and may play causative role


CLINICAL ISSUES




• Symptoms most often similar to acute cholecystitis, but can be chronic and mimic malignancy

• More common in females during 6th or 7th decade of life

• Only definitive treatment is cholecystectomy

image
(Left) Resected GB shows marked wall thickening image and an intramural abscess image. A portion of the adjacent liver image was resected because of the high intraoperative suspicion of GB cancer. Pathology revealed xanthogranulomatous cholecystitis (XGC).


image
(Right) Axial CECT shows a thickened wall of the gallbladder, especially the fundus image, with an indistinct border with the liver. While the appearance was concerning for gallbladder cancer, this was found to be XGC at cholecystectomy.

image
(Left) Axial CECT of a patient with RUQ pain shows marked irregular GB wall thickening image, intramural low attenuation image, and several pericholecystic collections image. Low-attenuation intramural nodules in XGC are due to either abscesses or xanthogranulomas.


image
(Right) Axial NECT in a patient with chronic abdominal pain shows a distended, thick-walled gallbladder exhibiting indistinct margins with the liver image. While this was worrisome for carcinoma, XGC was confirmed at surgery.


TERMINOLOGY


Abbreviations




• Xanthogranulomatous cholecystitis (XGC)


Synonyms




• Fibroxanthogranulomatous cholecystitis; xanthogranulomatous cholangitis


Definitions




• Rare inflammatory disorder of gallbladder (GB) characterized by accumulation of lipid-laden macrophages and fibrous tissue


IMAGING


General Features




• Best diagnostic clue
image GB wall thickening with intramural low-attenuation/hypoechoic nodules or bands corresponding to foamy cell infiltrates or abscesses

• Location
image GB wall

image Pericholecystic space

image Main lobar hepatic fissure


Imaging Recommendations




• Best imaging tool
image CECT or MR


CT Findings




• Imaging findings overlap with acute cholecystitis, chronic cholecystitis, and gallbladder carcinoma
image GB wall may be focally or diffusely thickened (± loss of normal wall definition)
– GB wall may demonstrate poor enhancement

image Low-attenuation intramural nodules and bands corresponding to foamy cell infiltrate and areas of necrosis/abscess
– Intramural nodule may occupy > 60% of wall surface

– Most unique imaging feature for XGC

image Pericholecystic fluid, inflammatory change, and induration ± fistulous tracts, abscesses, contained perforation, etc.
– Inflammation can extend to involve adjacent liver (blurring margin between GB and liver), and thus mimic GB cancer with hepatic invasion

image Adjacent focal hyperperfusion of liver/transient hepatic attenuation difference (THAD)

image Gallstones almost always present but not always visible on CT

image Local lymphadenopathy frequent (usually reactive due to inflammation)

• Helpful findings to differentiate XGC from GB carcinoma
image More commonly diffuse wall thickening (rather than focal)

image Continuous mucosal line of enhancement

image Intramural low-attenuation nodules

image Absence of hepatic invasion

image Absence of biliary dilatation

image Presence of 3 findings leads to 83% sensitivity, 100% specificity, and 91% accuracy for differentiation of XGC from GB carcinoma


MR Findings




• Gallbladder wall thickening (diffuse > focal) with intramural T2 hyperintensity
image Areas of xanthogranulomatosis are iso- or slightly T2 hyperintense

image Areas of necrosis and abscess are highly T2 hyperintense

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Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Xanthogranulomatous Cholecystitis

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