Giant Fibrous Polyp of the Gallbladder Showing a Periphery-Dominant Contrast Enhancement: How to Differentiate It From Early Carcinoma

Abstract

Although polyp size and stalk diameter are significant for the differential diagnosis of a gallbladder polyp, it is necessary to catch genuine polyp characteristics to differentiate a giant fibrous polyp from gallbladder carcinoma (GBC). This case report analyses the images and their correlation with the pathology. Transabdominal sonography revealed gallstones and a giant pedunculated gallbladder polyp measuring 32 × 18 × 14 mm with a thick stalk. The polyp lacked a hyperechoic surface line and was not delineated by either a deep hypoechoic area or a conically thickened outermost hyperechoic layer. Contrast-enhanced ultrasonography (CEUS) depicted a periphery-dominant enhancement, during the post vascular phase. A noncontrast computed tomogram (CT) did not demonstrate a gallbladder mass; meanwhile, a dynamic study revealed an enhanced polyp showing a periphery-dominant enhancement. Hence, without diagnostic findings suggestive of an obvious advanced GBC or excluding an early GBC, a full-thickness laparoscopic cholecystectomy was performed. The histopathology demonstrated a fibrous polyp with a thick stalk. In conclusion, a giant gallbladder polyp with a thick stalk showing a periphery-dominant contrast enhancement could suggest a fibrous polyp.