Mucin-producing pancreatic tumors: historical review of its nosological concept.

A brief historic outline of the problem of mucin-producing pancreatic tumors is presented. Based on the authors' observations, clinical aspects and pathomorphology of these tumors have been described. The authors propose their own classification of this tumor type which is based on the literature published so far. Their classification also takes into account the localization of lesions. Reference is made to the concept described by the term "mucinous ductetatic/cystic lesions" (MDCL) and it is also pointed out that mucinous carcinoma may develop on the background of MDCL. Since the appearance of the term "mucus secreting pancreatic cancer" or "mucin-producing pancreatic tumor", many similar and/or related conditions have been described especially in Japan under the same or different names. However, there seems to be some confusion about the concept of this condition not only among clinicians but also among pathologists. In addition, another entity, mucinous cystic neoplasms of the pancreas, was proposed and may have provided some overlap with the former conditions in its concept. Furthermore, definitions of these two conditions varied according to the authors. In this paper, therefore, we review and critically analyze cases of mucin-producing pancreatic tumor (MPPT) as well as mucinous cystic neoplasm (MCN) of the pancreas, and intend to classify them under a generic term, i.e. "mucinous ductectatic/cystic lesions (MDCL) of the pancreas".