Intraductal papillary-mucinous neoplasms and mucinous cystic neoplasms of the pancreas differentiated by ovarian-type stroma

Background. Intraductal papillary-mucinous neoplasms (IPMN) and mucinous cystic neoplasms (MCN) of the pancreas have similar clinicopathologic findings. This study was intended to clarify clinicopathologic characteristics in IPMNs and MCNs differentiated by ovarian-type stroma. Methods. Medical records for 77 patients with pancreatic cystic neoplasms with mucin secretion were reviewed. Patients were divided into IPMN (n = 70) or MCN (n = 7) according to the presence of ovarian-type stroma, and clinicopathologic parameters were compared between groups. Results. IPMNs consisted of 32 adenomas, 12 borderline neoplasms, 13 adenocarcinomas in situ, and 13 invasive adenocarcinomas, MCNs included 6 adenomas and 1 invasive adenocarcinoma. The mean age of IPMN patients (66 years) was significantly older than that of MCN patients (55 years). The male:female ratio in IPMN (53/17) was significantly greater (P < .001) than in MCN (0/7). The location of the pancreatic mass differed, with 76% of IPMNs occurring in the head, while 86% of MCNs occurred in the body or tail. Mass mean size was significantly smaller (28 mm vs 78 mm, P < .001), and mean diameter of the main pancreatic duct was larger (6.8 mm vs 3.1 mm, P < .001) in IPMN than in MCN. Patulous papilla was present in 44% (31/70) of IPMNs, but none was present in MCNs. Communication between the cyst and main pancreatic duct was more frequent in IPMNs (67/70) than in MCNs (1/7). Overall 5-year survival rates were 84% (IPMN) and 100% (MCN). Conclusions. Clinicopathologic differences between IPMN and MCN are much clearer when differentiated by presence of ovarian-type stroma. Favorable prognosis for both neoplasms is offered by complete resection.