Kwak Heewon A, Liu Xiuli, Allende Daniela S, Pai Rish K, Hart John, Xiao Shu-Yuan
Department of Pathology, University of Chicago, Chicago, IL, USA.
Department of Pathology, University of Florida, Gainesville, FL, USA.
Mod Pathol. 2016 Sep;29(9):977-84. doi: 10.1038/modpathol.2016.93. Epub 2016 May 20.
Intraductal papillary mucinous neoplasm is considered a precursor lesion to pancreatic adenocarcinoma. These are further classified into four histologic subtypes: gastric, intestinal, pancreatobiliary, and oncocytic. The first aim of this study was to assess the interobserver variability among five gastrointestinal pathologists in diagnosing intraductal papillary mucinous neoplasm subtypes by morphology alone. The second aim of the study was to compare intraductal papillary mucinous neoplasm subtypes, which received consensus diagnoses (≥80% agreement) with their respective mucin immunoprofiles (MUC1, MUC2, MUC5AC, MUC6, and CDX2). A consensus histologic subtype was reached in 58% of cases (29/50) among the five gastrointestinal pathologists. Overall there was moderate agreement (κ=0.41, P<0.01) in subtyping intraductal papillary mucinous neoplasms without the use of immunohistochemistry. The histologic subtype with the best interobserver agreement was intestinal type (κ=0.56, P<0.01) followed by pancreatobiliary, gastric, mixed, and oncocytic types (κ=0.43, P<0.01; κ=0.38, P<0.01; κ=0.17, P<0.01; κ=0.08, P<0.04, respectively). Both kappa values for mixed and oncocytic subtypes were likely artificially low due to the underrepresentation of these subtypes in this study and not a true indication of poor interobserver agreement. Following an intradepartmental consensus meeting between two gastrointestinal pathologists, 68% of cases (34/50) received a consensus intraductal papillary mucinous neoplasm subtype. Sixty-nine percent of cases (11/16) that did not receive a consensus intraductal papillary mucinous neoplasm subtype could be classified based on their respective immunoprofiles. Standardizing the use of immunohistochemistry with a mucin immunopanel (MUC1, MUC2, MUC5AC, and MUC6) may improve the agreement of diagnosing intraductal papillary mucinous neoplasm histologic subtypes.
导管内乳头状黏液性肿瘤被认为是胰腺腺癌的前驱病变。这些肿瘤进一步分为四种组织学亚型：胃型、肠型、胰胆管型和嗜酸细胞型。本研究的首要目的是评估五位胃肠病理学家仅通过形态学诊断导管内乳头状黏液性肿瘤亚型时的观察者间变异性。该研究的第二个目的是比较获得共识诊断（≥80%一致率）的导管内乳头状黏液性肿瘤亚型与其各自的黏蛋白免疫表型（MUC1、MUC2、MUC5AC、MUC6和CDX2）。五位胃肠病理学家对58%的病例（29/50）达成了一致的组织学亚型诊断。总体而言，在不使用免疫组化的情况下，对导管内乳头状黏液性肿瘤进行亚型分类时存在中度一致性（κ=0.41，P<0.01）。观察者间一致性最好的组织学亚型是肠型（κ=0.56，P<0.01），其次是胰胆管型、胃型、混合型和嗜酸细胞型（分别为κ=0.43，P<0.01；κ=0.38，P<0.01；κ=0.17，P<0.01；κ=0.08，P<0.04）。由于本研究中混合型和嗜酸细胞型亚型的病例数较少，这两种亚型的kappa值可能人为偏低，并非观察者间一致性差的真实反映。在两位胃肠病理学家进行部门内部共识会议后，68%的病例（34/50）获得了一致的导管内乳头状黏液性肿瘤亚型诊断。69%未获得一致的导管内乳头状黏液性肿瘤亚型诊断的病例（11/16）可根据其各自的免疫表型进行分类。使用黏蛋白免疫组化面板（MUC1、MUC2、MUC5AC和MUC6）标准化免疫组化的使用可能会提高导管内乳头状黏液性肿瘤组织学亚型诊断的一致性。
