Intracholecystic papillary-tubular neoplasm in a patient with choledochal cyst: a link between choledochal cyst and gallbladder cancer?

Background Intracholecystic papillary-tubular neoplasms are rare precursor lesions of gallbladder cancer. They were proposed as a separate pathologic entity in 2012 by Adsay et al. for the unification of a variety of mass-forming precursor lesions including papillary adenomas, tubulopapillary adenomas, intestinal adenomas, and others. They are considered homologous to intrapapillary mucinous neoplasms of the pancreas and intrabiliary papillary neoplasms of the common bile duct. In contrast with the commoner flat-type precursor gallbladder cancer lesions, they follow a more indolent clinical course and probably different genetic pathways to carcinogenesis. They are largely uninvestigated with only a handful of studies providing biological and clinical information. Choledochal cysts are dilation of the common bile duct. Diagnosis is usually established during childhood, and only a minority of patients are diagnosed at adulthood. They are of major clinical importance as they are known predisposing factors for biliary carcinogenesis.