The risk of biliary tract adenocarcinoma developing in a patient with a choledochal cyst left in situ is approximately which of the following?

b. 3% to 5%

Adenocarcinoma of the biliary tract develops in 3% to 5% of patients who have choledochal cysts. Although this represent a small number of patients, the total number reported exceeds 50 and the incidence is about 1000 times that of the normal population. In addition, the carcinoma may develop as early as the adolescent years, a marked contrast to the normal population in which a fifth or sixth decade of life presentation is typical. Neoplastic transformation of the dysplastic biliary cyst epithelium may result from chronic inflammation. Consideration of this potential problem has contributed significantly to the current emphasis on surgical excision of these cysts.