Xanthogranulomatous Cholecystitis

Published on 18/07/2015 by admin

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Last modified 18/07/2015

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 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
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