Hyperplastic Cholecystoses

Published on 09/08/2015 by admin

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Last modified 09/08/2015

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 Adenomyomatosis: Mural GB wall thickening due to formation of intramural diverticula (Rokitansky-Aschoff sinuses) with smooth muscle and epithelial proliferation

image Cholesterolosis: Deposition of foamy, cholesterol-laden histiocytes in subepithelium of GB

IMAGING

• Adenomyomatosis

image US: Focal, segmental, or diffuse wall thickening with anechoic intramural spaces, intramural echogenic foci ± acoustic shadowing, “comet tail” artifacts, & twinkle artifact
image MR: High-signal cystic spaces (with curvilinear arrangement) on T2WI/MRCP within focally or diffusely thickened GB wall (string of beads or pearl necklace sign)
image CT: Segmental/diffuse GB wall thickening (may present as fundal enhancing soft tissue nodule)

– Cystic nonenhancing spaces within thickened GB wall
• Cholesterolosis

image US: Multiple small (< 10 mm) nonshadowing iso-/hyperechoic polyps with “comet tail” & twinkle artifact
image MR: Small, round polyps with intermediate T1/T2 signal
image CT: Usually imperceptible

CLINICAL ISSUES

• Virtually always asymptomatic, but may very rarely present with RUQ pain
• Almost always an incidental finding with no significance

image Must be correctly differentiated from malignancy based on imaging appearance
image Adenomyomatosis may rarely require cholecystectomy if symptomatic or if imaging findings are equivocal and there is concern for GB carcinoma
image Cholesterol polyps may be resected when large or when growth is documented
image
(Left) Schematic drawing of adenomyomatosis illustrates a thickened gallbladder (GB) wall with multiple intramural cystic spaces image.

image
(Right) Ultrasound of an elderly woman with right upper quadrant pain shows tiny echogenic foci image within the anterior wall of the GB and posterior “comet tail” artifacts image. This appearance is likely caused by reverberation of the ultrasound pulse within cholesterol crystals in the GB subepithelium.
image
(Left) Ultrasound image demonstrates diffuse thickening of the GB wall with numerous foci of “comet tail” artifact image, classic for adenomyomatosis. Note the presence of a gallstone image, found in 90% of cases.

image
(Right) Color Doppler ultrasound demonstrates “twinkle” artifact image associated with the echogenic reflectors within the thickened GB wall. “Comet tail” and twinkle artifacts are due to reverberation within cholesterol deposited within epithelial penetrations (Rokitansky-Aschoff sinuses).

TERMINOLOGY

Synonyms

• Cholesterolosis: Strawberry gallbladder (GB), cholesterol polyp
• Adenomyomatosis: GB diverticulosis, cholecystitis glandularis proliferans, adenomyomatous hyperplasia

Definitions

• Idiopathic, nonneoplastic, and noninflammatory proliferative disorder that results in GB wall thickening

image Subclassified into 2 entities
image Adenomyomatosis

– Mural GB wall thickening due to exaggeration of normal luminal epithelial folds and formation of intramural diverticula (Rokitansky-Aschoff sinuses) in conjunction with smooth muscle and GB epithelial proliferation
image Cholesterolosis

– Deposition of foamy, cholesterol-laden histiocytes in subepithelium of GB
– Numerous small accumulations (strawberry GB) or larger polypoid deposit (cholesterol polyp)

IMAGING

General Features

• Best diagnostic clue

image Adenomyomatosis

– Focal (typically fundal) or diffuse GB wall thickening with intramural cystic spaces containing echogenic foci and “comet tail” artifacts
image Cholesterolosis

– Echogenic GB polyps with associated “comet tail” artifact
• Location

image Cholesterolosis: Superficial GB wall (epithelium)
image Adenomyomatosis: Deep GB wall (muscular layer)

– Fundal (most common), segmental mid-body (“hourglass” configuration of GB), or diffuse
• Size

image Cholesterol polyps typically 5-10 mm

CT Findings

• Adenomyomatosis

image Segmental or diffuse GB wall thickening

– May present as fundal enhancing soft tissue nodule
image Cystic nonenhancing spaces (Rokitansky-Aschoff sinuses) within thickened GB wall (usually within fundal mass)

– Cystic spaces most important feature to differentiate adenomyomatosis from GB carcinoma
– Ancillary findings favoring adenomyomatosis: Smooth borders without evidence of biliary ductal dilatation, hepatic invasion, or regional adenopathy
image Often brisk wall enhancement post contrast
• Cholesterolosis: Subepithelial cholesterol and small cholesterol polyps usually imperceptible on CT

MR Findings

• Cholesterolosis

image Small, round, intraluminal polyps juxtaposed against low T1WI signal and high T2WI signal bile

– Nodules are homogeneous and of intermediate signal intensity on both T1WI and T2WI
– Nodules are directly attached to GB wall
• Adenomyomatosis

image T1-hypointense foci within thickened GB wall corresponding to bile-filled intramural diverticula

– Occasionally T1-hyperintense due to inspissated bile/debris within Rokitansky-Aschoff sinuses
image T2WI/MRCP high signal cystic spaces (with a curvilinear arrangement) within focally or diffusely thickened GB wall (string of beads or pearl necklace sign)
image Cystic spaces show no enhancement on T1WI C+ images
image Diffusion weighted imaging (DWI) not a reliable means of distinguishing cancer from adenomyomatosis
• MR is highly accurate (> 90%) in differentiation of adenomyomatosis from GB carcinoma

Ultrasonographic Findings

• Grayscale ultrasound

image Adenomyomatosis

– Focal, segmental, or diffuse wall thickening

image Focal or localized form the most common, usually affecting GB fundus
image Segmental form causes annular thickening of GB wall, resulting in strictures: Annular thickening in GB mid body results in “hourglass” appearance
image 

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