PanIN or IPMN? Redefining Lesion Size in 3 Dimensions

Area of Science:

• Gastroenterology
• Oncology
• Medical Imaging

Background:

• Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs).
• Current clinical classification of PanIN and IPMN relies on 2D histology and 3D computed tomography (CT) imaging, with size being a primary differentiator.
• This classification system faces challenges due to the inherent limitations of 2D evaluation of 3D structures.

Purpose of the Study:

• To investigate the accuracy of current PanIN and IPMN classification in high-resolution 3D imaging.
• To characterize the size and prevalence of PanINs within the 3D architecture of the pancreas.
• To determine if lesions classified as PanIN in 2D meet IPMN criteria when considered in 3D.

Main Methods:

• Analysis of 47 thick pancreatic tissue slabs from grossly normal surgical resections.
• Construction of cellular-resolution 3D maps to identify and measure ductal precursor lesions.
• Re-evaluation of preoperative CT scans for lesions identified in 3D.

Main Results:

• Over 1400 ductal precursor lesions meeting 2D PanIN size criteria were identified.
• When analyzed in 3D, 25 of these lesions met the 2D size criteria for IPMN.
• Nearly half of these larger, 3D-defined IPMN precursor lesions were visible on preoperative CT scans.

Conclusions:

• The current clinical classification system for PanIN and IPMN is inadequate for evaluating high-resolution 3D pancreatic structures.
• There is a need to revise classification guidelines to better incorporate 3D spatial information.
• Improved classification methods are essential for accurate diagnosis and management of pancreatic precursor lesions.