Endoscopic ultrasonography for differential diagnosis of polypoid gall bladder lesions: analysis in surgical and follow up series.

BACKGROUND Differential diagnosis is often difficult for small (</=20 mm) polypoid lesions of the gall bladder. AIM To assess the diagnostic accuracy of endoscopic ultrasonography (EUS) for polypoid lesions in a surgical and follow up series. METHODS A total of 194 patients with small polypoid lesions underwent both ultrasonography and EUS. A tiny echogenic spot or an aggregation of echogenic spots and multiple microcysts or a comet tail artefact indicated cholesterol polyp and adenomyomatosis respectively. Other lesions were diagnosed as neoplastic (adenoma or adenocarcinoma). In the 58 patients who underwent surgery, the histological diagnoses were cholesterol polyp (n = 36), adenomyomatosis (n = 7), adenoma (n = 4), and adenocarcinoma (n = 11). Of the remaining 136 patients with an EUS diagnosis of non-neoplastic lesions, 125 were followed up with ultrasonography alone or with EUS for 1-8.7 years (mean 2.6 years). RESULTS In the surgical series, EUS (97%) differentiated polypoid lesions more precisely than ultrasonography (76%). During follow up, the lesions remained unchanged in size in 109 (87%) of the 125 patients with non-neoplastic lesions diagnosed by EUS. No neoplastic lesions developed in these patients. Ultrasonography had shown lesions to be neoplastic in 13% of the follow up series. CONCLUSIONS EUS is highly accurate for differentially diagnosing polypoid gall bladder lesions. It is recommended when ultrasonography cannot rule out neoplastic lesions. Non-neoplastic lesions diagnosed by EUS may be followed and observed with ultrasonography.