g i d n n b [ c a F o t n abdominal ultrasound on a routine physical examination f an asymptomatic 59-year-old man showed gallbladder enargement. Contrast-enhanced computed tomography showed mass in the cystic duct (Fig. 1). Endoscopic retrograde holangiopancreatography showed complete obstruction of the ystic duct without abnormal findings of the common bile duct Fig. 2). Under the diagnosis of restricted carcinoma of the ystic duct, a pancreatoduodenectomy with lymphadenectomy as performed. In the resected specimen, a nodular-type tumor easuring 12 3 mm was found in the cystic duct. The tumor as diagnosed histopathologically as a poorly differentiated ubular adenocarcinoma with infiltration into the subserosal ayer, but with no lymph node metastasis (TNM classification: 2, N0, M0; stage IB). The postoperative course was uneventul and the patient is without recurrence at 5 years.