Intraductal papillary mucinous carcinoma with atypical manifestations: report of two cases.

Intraductal papillary mucinous neoplasms (IPMNs) are a well-characterized group of mucin-producing cystic neoplasms of the clear malignant potential type. We report here two cases of intraductal papillary mucinous carcinoma (IPMC) with atypical manifestations. In one case, we discussed a pseudomyxoma peritonei caused by a ruptured IPMC. In the other case we discussed the fistulization of IPMC into the stomach and duodenum. These two cases suggest that IPMN can either spontaneously rupture causing mucinous materials to spill into the free abdominal cavity or directly invade adjacent organs resulting in fistula development.