A large inflammatory polyp of the gallbladder masquerading as gallbladder carcinoma

An inflammatory polyp of the gallbladder is a rare variant of benign gallbladder polyp. Differentiation between an inflammatory polyp and polypoid gallbladder carcinoma is difficult when the polyp is more than 1 cm in diameter. We report a rare case of a large inflammatory polyp of the gallbladder masquerading as gallbladder carcinoma in a 37-year-old Japanese woman who was incidentally diagnosed with a large gallbladder polyp, measuring 1 cm in diameter, by ultrasonography. She was asymptomatic and physical examination was unremarkable. Abdominal ultrasonography and endoscopic ultrasonography revealed three polypoid lesions in the gallbladder. One lesion was an isoechoic polyp, measuring 15 x 8 mm, showing a nodular surface and located in the fundus of the gallbladder. The other two lesions were hyperechoic polyps, measuring 5 x 5 mm, in the body of the gallbladder. Computed tomography and magnetic resonance imaging revealed marked enhancement of the largest polypoid lesion by dynamic study, and no lymph node enlargement was noted. Endoscopic retrograde cholangiography revealed a 12 x 8 mm polyp with an irregular surface in the fundus of the gallbladder. Superselective angiography of the cystic artery revealed neovascularity and a tumor stain in the fundus of the gallbladder. Cholecystectomy with lymph node dissection was performed. Intraoperative frozen section diagnosis of the largest polyp was an inflammatory polyp of the gallbladder. The other two polyps were cholesterol polyps. Inflammatory polyp should be considered as a differential diagnosis of hypervascular gallbladder polyps that measure more than 1 cm in diameter.