Pancreatic ductal adenocarcinoma (PDAC) develops from 2 known precursor lesions: a majority (∼85%) develops from pancreatic intraepithelial neoplasia (PanIN), and a minority develops from intraductal papillary mucinous neoplasms (IPMNs). Clinical classification of PanIN and IPMN relies on a combination of low-resolution, 3-dimensional (D) imaging (computed tomography, CT), and high-resolution, 2D imaging (histology). The definitions of PanIN and IPMN currently rely heavily on size. IPMNs are defined as macroscopic: generally >1.0 cm and visible in CT, and PanINs are defined as microscopic: generally <0.5 cm and not identifiable in CT. As 2D evaluation fails to take into account 3D structures, we hypothesized that this classification would fail in evaluation of high-resolution, 3D images. To characterize the size and prevalence of PanINs in 3D, 47 thick slabs of pancreas were harvested from grossly normal areas of pancreatic resections, excluding samples from individuals with a diagnosis of an IPMN. All patients but one underwent preoperative CT scans. Through construction of cellular resolution 3D maps, we identified >1400 ductal precursor lesions that met the 2D histologic size criteria of PanINs. We show that, when 3D space is considered, 25 of these lesions can be digitally sectioned to meet the 2D histologic size criterion of IPMN. Re-evaluation of the preoperative CT images of individuals found to possess these large precursor lesions showed that nearly half are visible on imaging. These findings demonstrate that the clinical classification of PanIN and IPMN fails in evaluation of high-resolution, 3D images, emphasizing the need for re-evaluation of classification guidelines that place significant weight on 2D assessment of 3D structures.

中文翻译：

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PanIN 还是 IPMN？从 3 个维度重新定义病变大小。


胰腺导管腺癌 (PDAC) 由 2 种已知的前驱病变发展而来：大多数 (~85%) 由胰腺上皮内瘤变 (PanIN) 发展而来，少数由导管内乳头状粘液性肿瘤 (IPMN) 发展而来。 PanIN 和 IPMN 的临床分类依赖于低分辨率 3 维 (D) 成像（计算机断层扫描，CT）和高分辨率 2D 成像（组织学）的组合。 PanIN 和 IPMN 的定义目前严重依赖于大小。 IPMN 被定义为肉眼可见的：通常 >1.0 cm 并且在 CT 中可见，PanIN 被定义为微观的：通常 <0 id=89>1400 个符合 PanIN 二维组织学尺寸标准的导管前体病变。我们表明，当考虑 3D 空间时，可以对其中 25 个病变进行数字切片以满足 IPMN 的 2D 组织学大小标准。对发现具有这些大的前驱病变的个体的术前 CT 图像进行重新评估表明，近一半的病变在成像中可见。这些发现表明，PanIN 和 IPMN 的临床分类无法评估高分辨率 3D 图像，强调需要重新评估分类指南，这些指南非常重视 3D 结构的 2D 评估。