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Background Pancreatic mucinous cystic neoplasms (MCNs) are rare mucin-producing cystic tumours defined by the presence of ovarian-type stroma. MCNs have a malignant potential and thus surgery is frequently performed. The aim of this cohort study was to define better the criteria for surgical resection in patients with MCN. Methods This multicentre retrospective study included all resected MCNs between 2003 and 2015 in participating centres. Lesions without ovarian-type stroma were excluded. Patient characteristics, preoperative findings, histopathology findings and follow-up data were recorded. Results The study included 211 patients; their median age was 53 (range 18–82) years, and 202 (95·7 per cent) were women. Median preoperative tumour size was 55 (range 12–230) mm. Thirty-four of the 211 (16·1 per cent) were malignant, and high-grade dysplasia (HGD) was found in a further 13 (6·2 per cent). One-third of MCNs in men were associated with invasive cancer, compared with 15·3 per cent in women. Five cases of malignant transformation occurred in MCNs smaller than 4 cm. All cases of malignancy or HGD were associated with symptoms or features of concern on preoperative cross-sectional imaging. In multivariable analysis, raised carbohydrate antigen 19-9 (odds ratio (OR) 10·54, 95 per cent c.i. 2·85 to 218·23; P < 0·001), tumour size (OR 4·23, 3·02 to 11·03; P = 0·001), mural nodules (OR 3·55, 1·31 to 20·55; P = 0·002) and weight loss (OR 3·40, 2·34 to 12·34; P = 0·034) were independent factors predictive of malignant transformation. Conclusions Small indeterminate MCNs with no symptoms or features of concern may safely be observed as they have a low risk of malignant transformation.

Item does not contain fulltext BACKGROUND: The current management of pancreatic mucinous cystic neoplasms (MCN) is defined by the consensus European, International Association of Pancreatology and American College of Gastroenterology guidelines. However, the criterion for surgical resection remains uncertain and differs between these guidelines. Therefore through this systematic review of the existing literature we aimed to better define the natural history and prognosis of these lesions, in order to clarify recommendations for future management. METHODS: A systematic literature search was performed (PubMed, EMBASE, Cochrane Library) for studies published in the English language between 1970 and 2015. RESULTS: MCNs occur almost exclusively in women (female:male 20:1) and are mainly located in the pancreatic body or tail (93-95%). They are usually found incidentally at the age of 40-60 years. Cross-sectional imaging and endoscopic ultrasound are the most frequently used diagnostic tools, but often it is impossible to differentiate MCNs from branch duct intraductal papillary mucinous neoplasms (BD-IPMN) or oligocystic serous adenomas pre-operatively. In resected MCNs, 0-34% are malignant, but in those less than 4 cm only 0.03% were associated with invasive adenocarcinoma. No surgically resected benign MCNs were associated with a synchronous lesion or recurrence; therefore further follow-up is not required after resection. Five-year survival after surgical resection of a malignant MCN is approximately 60%. CONCLUSIONS: Compared to other pancreatic tumors, MCNs have a low aggressive behavior, with exceptionally low rates of malignant transformation when less than 4 cm in size, are asymptomatic and lack worrisome features on pre-operative imaging. This differs significantly from the natural history of small BD-IPMNs, supporting the need to differentiate mucinous cyst subtypes pre-operatively, where possible. The findings support the recommendations from the recent European Consensus Guidelines, for the more conservative management of MCNs.

Background & Aims The association between pancreatic intraductal papillary mucinous neoplasms (IPMNs) and extrapancreatic neoplasms (EPNs) is controversial. We performed a multicenter observational study to assess the incidence of EPNs after an IPMN diagnosis. Methods 1340 patients with IPMNs were evaluated from 2000 through 2013 at 4 academic institutions in Europe for development of EPN. To estimate the actual incidence of EPN, we excluded patients with an EPN previous or synchronous to the IPMN, and patients who had been followed for less than 12 months, resulting in a study population of 816 patients. The incidence of EPN was compared with sex-specific, age-adjusted European cancer statistics; the standardized incidence ratio (SIR), and the 5- and 10-year cumulative incidence rates were calculated. Results A total of 290/1340 patients had a history of EPN (prevalence of 21.6%). In this subgroup of patients, the IPMN was discovered incidentally in 241. Among the 816 patients included in the incidence analysis, 50 developed an EPN after a median time of 46 months from study enrollment. The incidence of any EPN was not greater in patients with than without IPMN with a SIR of 1.48 (95% confidence interval, 0.94–2.22) in males and of 1.39 (95% CI 0.90–2.05) in females. The 5- and 10-year cumulative incidence rates for development of EPN in patients with IPMN were 7.9% and 16.6% in men, and 3.4% and 23.1% in women. Conclusions Patients with IPMN do not have a significantly higher incidence of EPNs than the general European population. It might not be necessary to screen patients with IPMN for EPN.