Signet ring cell carcinoma of the lower bile duct with rapid growth: report of a case

Signet ring cell carcinoma occurring in the biliary tract is extremely rare. We herein report the case of a 78-year-old Japanese woman demonstrating signet ring cell carcinoma of the lower bile duct with a rapid growth. Computed tomography of the pancreas head pointed out a circular thickness in the lower bile ductal wall and stenosis of the common bile duct. Cholangiography revealed tapering stenosis at the lower bile duct. Biopsy specimens taken from these lesions and scratched specimens taken from stenotic portion of the lower bile duct were analyzed and demonstrated signet ring cell carcinoma. To the best of our knowledge, this is the first reported case of primary signet ring cell carcinoma of the lower bile duct reported in the English literature. Based on our experience, signet ring cell carcinoma of the lower bile duct is considered to demonstrate both transmural dispersion and an aggressive nature.