Bile duct cancer developed after cyst excision for choledochal cyst

Oncogenesis after cyst excision for choledochal cyst and suitable surgical procedures for this operation are discussed. The clinical data of 23 patients with cancer of the biliary tree after excision of choledochal cyst reported in the English-language and Japanese literature were reviewed, and data for 1353 Japanese patients with choledochal cyst and/or pancreaticobiliary malunion were analyzed. In the 23 patients reported in the literature, age at cyst excision ranged from 1 to 55 years (average, 23.0 ± 13.7 years), and cancers were detected at age 18—60 years (average, 32.1 ± 12.2 years), with intervals between cyst excision and cancer detection of 1—19 years (average, 9.0 ± 5.5 years). Sites of cancer development were: intrahepatic, six; anastomotic, eight; hepatic side residual cyst, three; and the intrapancreatic duct, six. In the Japanese patients with choledochal cyst and/or pancreaticobiliary malunion, the incidence of cancer associated with primary choledochal cyst and/or pancreaticobiliary malunion was 16.2% (219/1353). The incidence of cancer development after cyst excision in this population, of whom 1291/1353 underwent surgery, was assumed to be 0.7%. Nearly half of the 23 patients in the literature had undergone inadequate cyst excision. Oncogenesis of cancers after cyst excision is possibly different from that of choledochal cysts.