Ductectatic‐type Mucinous Cystadenoma and Cystadenocarcinoma of the Human Pancreas: A Novel Clinicopathological Entity

A new type of mucinous cystic pancreatic neoplasm is described. The lesions, which have been recognized only recently with the progress of diagnostic techniques and have not previously been described in the literature, are characterized by multilocular cysts with papillary proliferation of the lining epithelium. They occur exclusively in the head and body, predominantly in males, and coexistence of well‐differentiated adenocarcinoma as well as adenoma components is frequently encountered. These lesions are quite different from hitherto described mucinous cystic neoplasms of pancreas, not only in terms of gross features but also with regard to intrapancreatic location, and sex and age distributions. We propose to classify these lesions as a new pancreatic tumor entity: the ductectatic‐type mucinous cystadenoma/cystadenocarcinoma.