Objective Invasive cancers arising from intraductal papillary mucinous neoplasm (IPMN) are recognised as a morphologically and biologically heterogeneous group of neoplasms. Less is known about the epithelial subtypes of the precursor IPMN from which these lesions arise. The authors investigate the clinicopathological characteristics and the impact on survival of both the invasive component and its background IPMN. Design and patients The study cohort comprised 61 patients with invasive IPMN (study group) and 570 patients with pancreatic ductal adenocarcinoma (PDAC, control group) resected at a single institution. Multivariate analyses were performed using a stage-matched Cox proportional hazard model. Results The histology of invasive components of the IPMN cohort was tubular in 38 (62%), colloid in 16 (26%), and oncocytic in seven (12%). Compared with PDAC, invasive IPMNs were associated with a lower incidence of adverse pathological features and improved mortality by multivariate analysis (HR 0.58; 95% CI 0.39 to 0.86). In subtype analysis, this favourable outcome remained only for colloid and oncocytic carcinomas, while tubular adenocarcinoma was associated with worse overall survival, not significantly different from that of PDAC (HR 0.85; 95% CI 0.53 to 1.36). Colloid and oncocytic carcinomas arose only from intestinal-and oncocytic-type IPMNs, respectively, and were mostly of the main-duct type, whereas tubular adenocarcinomas primarily originated in the gastric background, which was often associated with branch-duct IPMN. Overall survival of patients with invasive adenocarcinomas arising from gastric-type IPMN was significantly worse than that of patients with non-gastric-type IPMN (p=0.016). Conclusions Tubular, colloid and oncocytic invasive IPMNs have varying prognosis, and arise from different epithelial subtypes. Colloid and oncocytic types have markedly improved biology, whereas the tubular type has a course that resembles PDAC. Analysis of these subtypes indicates that the background epithelium plays an equally, if not more, important role in defining the biology and prognosis of invasive IPMNs.

SUMMARYBackgrounds: Neuroendocrine neoplasms in hepatobiliary organs are very rare, but several cases of

OBJECTIVES The objectives of this study were prospective evaluation of MR enterographic accuracy for detecting Crohn's disease imaging features in pediatric patients compared with a CT reference standard, as well as determination of MR enterographic accuracy for detecting active bowel inflammation and fibrosis using a histologic reference standard. MATERIALS AND METHODS The study group for this blinded prospective study included 21 pediatric subjects with known Crohn's disease scheduled for clinical CT imaging and histological bowel sampling for symptomatic exacerbation. All subjects and their parents gave informed consent to also undergo MR enterography. CT and MR enterography examinations were independently reviewed by 2 radiologists and scored for Crohn's disease features. All bowel histology specimens were reviewed by a single pathologist for presence of active mucosal inflammation and mural fibrosis, followed by imaging-histological correlation. RESULTS All 21 subjects underwent MR enterography and histological sampling, 18 of whom also underwent CT. MR enterography demonstrated high sensitivity for detecting Crohn's imaging features (bowel wall thickening, mesenteric inflammation, lymphadenopathy, fistula, abscess) compared with CT, with individual sensitivity values ranging from 85.1-100%. Out of a total of 53 abnormal bowel segments with MRI-histology correlation, MR enterography demonstrated 86.7% accuracy (90.0% sensitivity, 82.6% specificity) for detecting active inflammation (P < 0.001). Accuracy of MR enterography for detecting mural fibrosis overall was 64.9% compared with histology, but increased to 88.2% (P < 0.05) for detecting fibrosis without superimposed active inflammation. CONCLUSIONS MR enterography can substitute for CT as the first-line imaging modality in pediatric Crohn's patients, based on its ability to detect intestinal pathology in both small and large bowel as well as extraintestinal disease manifestations. Additionally, MR enterography provides an accurate noninvasive assessment of Crohn's disease activity and mural fibrosis and can aid in formulating treatment strategies for symptomatic patients and assessing therapy response.