松田 正道, 渡辺 五朗, 橋本 雅司, 宇田川 晴司

Masamichi MATSUDA, Goro WATANABE, Masaji HASHIMOTO, Harushi UDAGAWA

虎の門病院消化器外科

Department of Surgery, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, 105-8470, Japan

キーワード : Gallbladder polyp , Hyperplastic polyp , Multicystic appearance , Ultrasonography

Differential diagnosis of polypoid carcinoma of the gallbladder from such polypoid tumors as adenoma and hyperplasia is sometimes very difficult. Here we describe the sonographic features of a hyperplastic polyp of the gallbladder that appeared multicystic. The patient was a 51-year-old male who had been followed up by ultrasonography every 3 months because of his history of liver cirrhosis. No abnormalities had been detected in the gallbladder before October 1996, when a polypoid lesion was discovered. Abdominal ultrasonography showed a large polypoid lesion of about 22 mm in diameter at the fundus of the gallbladder. The polyp had a smooth surface and low internal echogenicity. Color Doppler ultrasound detected a slight blood flow in the neck of the polyp, and endoscopic ultrasonography showed the polyp to consist of many small cysts with a maximum diameter of about 5 mm. The polyp was enhanced on CT scanning. Histologic examination showed the polyp to be covered with papillary epithelium, to be formed from many dilated ductal structures, and to have marked interstitial edema. No cellular dysplasia was detected in the epithelium, and a diagnosis of hyperplastic polyp was made. Marked interstitial edema found in the polyp and the anechoic cystic areas on ultrasonography were thought to be edematous tissue. This case suggests that a multicystic appearance is a characteristic of hyperplastic polyps of the gallbladder.