Single or multiple small, round/ovoid masses attached to gallbladder (GB) wall with no posterior acoustic shadowing

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  Usually sessile but may be pedunculated with well-defined stalk

Usually 2-10 mm in size, most commonly in middle 1/3 of GB

Cholesterol polyp: Small with comet-tail artifact

Avascular or hypovascular on Doppler examination

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  Larger lesions may have slight internal vascularity

Consider neoplastic GB polyp if size > 10 mm, irregular outline, sessile morphology with abnormal GB wall and invasion of adjacent structures, growth on serial US examinations

Hyperplastic cholecystosis/adenomyomatosis

Nonshadowing cholelithiasis or sludge

Adenoma

Carcinoma or metastasis

Polypoid lesions include cholesterol polyp, adenomyomatosis, and neoplasms such as adenoma, carcinoma, and metastases

5% of population have polyps; 50% are cholesterol polyps

More common in middle age; F > M; incidental finding

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  < 6 mm: No follow-up

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  7-9 mm: Yearly US follow-up to monitor size

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  > 10 mm: Surgical consult

Scan in supine, decubitus (left or right lateral) positions to demonstrate immobility of GB polyp

Look for color flow in polyp and for any abnormality of adjacent GB wall, which might indicate cancer