title: Definition of MCN (mucinous cystic neoplasm of the pancreas) and a proposal for a new concept of MRN or MSN (mucinous round or spherical neoplasm).
abstract: The differential diagnosis of IPMN and MCN is very important for clinicians. MCN is reported to develop in middle-aged females (mean age 48 years) and in the body and tail of the pancreas. Some doctors insist that ovarian-like stroma is absolutely necessary for the definition of MCN. Prompt resection of MCN after diagnosis is desirable. In contrast, about 60% of cases with branch-type IPMN do not require an operation. Therefore, one of the important goals in the differential diagnosis of MCN and branch-type IPMN is to determine the surgical indications before the operation. We believe that MCN and IPMN should be defined by imaging procedures before the operation. We suggest that a neoplasm with an appearance similar to an orange should be diagnosed as MCN, while that with an appearance similar to a bunch of grapes in MRCP should be diagnosed as branch-type IPMN. Proposal of a new concept: If the term MCN is restricted to neoplasms that exhibit ovarian-like stroma, we propose that lesions which are surrounded by a very thick capsule, and which show an orange-like appearance by imaging procedures without histological ovarian-like stroma should be called MRN (mucinous round neoplasm) or MSN (mucinous spherical neoplasm).
authors.affiliation: Department of Gastroenterological and General Surgery, Yamagata University School of Medicine, Yamagata 990-9585, Japan. wkimura@med.id.yamagata-u.ac.jp
authors.forename: Wataru
authors.initials: W
authors.lastname: Kimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Nomura
authors.forename: Masaomi
authors.initials: M
authors.lastname: Mizutani
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Ma
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hirai
authors.forename: Akira
authors.initials: A
authors.lastname: Fuse
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D018297:Neoplasms, Cystic, Mucinous, and Serous / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D009626:Terminology as Topic; D014057:Tomography, X-Ray Computed