Differential diagnosis between gallbladder adenomas and cholesterol polyps on contrast-enhanced harmonic endoscopic ultrasonography

Differential diagnosis between gallbladder (GB) adenomas and cholesterol polyps based on ultrasonography or endoscopic ultrasonography (EUS) is challenging because they have similar echogenicity and morphology. We evaluated the usefulness of contrast-enhanced harmonic EUS (CEH-EUS) for differentiating between GB adenomas and cholesterol polyps. Between June 2010 and December 2011, a total of 87 patients with GB polyps who underwent a CEH-EUS were reviewed retrospectively. Of the 87 patients, 57 had a cholecystectomy. Of these, 34 patients were diagnosed with adenoma, cholesterol polyp, adenocarcinoma, or adenomyomatosis pathology. The remaining 23 patients were not diagnosed with GB polyps because their lesions separated from the GB mucosal layer during pathological sampling. On CEH-EUS, homogeneous and heterogeneous enhancement was shown in 6 and 2 patients with adenoma and in 4 and 8 patients with cholesterol polyps, respectively. Sensitivity and specificity of CEH-EUS for differential diagnosis of GB adenomas from cholesterol polyps based on the enhancement pattern were 75.0 and 66.6 %, respectively. CEH-EUS might be useful for distinguishing GB adenomas and cholesterol polyps based on enhancement patterns. However, an additional technique such as quantitative perfusion analysis is necessary because visual assessment of CEH-EUS images is subjective.