Fundic adenomyomatosis bulged with the subserosal excessive fat of the gallbladder mimicking polypoid carcinoma: A case report with unusual imaging and morphological features

This report describes a 41-year-old female who presented with adenomyomatosis of the gallbladder mimicking polypoid carcinoma, on the diagnostic imaging findings and revealing unusual histologic features for such a localized adenomyomatosis. The mass was located on the gallbladder liver-side wall at the fundus and papillary hyperechoic growth showed no clear ultrasonographic features of adenomyomatosis. The patient underwent a laparoscopic cholecystectomy with a tentative diagnosis of superficial polypoid carcinoma. Histologically, the tumor bulged due to subserosal excessive fat tissue.