A) Axial arterial phase preoperative computed tomography (CT) images of pancreatic IPMNs. B) Hematoxylin and eosin (H&E) images of resected IPMN tumor tissue. C) Bright-field micrographs (5x magnification) of organoid cultures derived from resected IPMN tumors and adjacent normal pancreatic tissue around day 7 or 8 unless noted otherwise. Case 1 (MCC-PANC-PDO-013): A. Moderate pancreatic ductal dilatation is present in the pancreatic tail (arrow). B. H&E (400X) shows high grade dysplasia of the mixed intestinal and gastric subtype characterized by pseudostratification with the nuclei remaining near the basal layer. The nuclei are vesicular with small nucleoli and visible goblet cells. Case 2 (MCC-PANC-PDO-017): A. Demonstrates diffuse irregular pancreatic main duct dilatation (arrows) compatible with main duct IPMN. B. H&E (200X) shows columnar cells with basally located nuclei that merge into neoplastic cells with pseudostratification and high-grade architectural features. Case 3 (MCC-PANC-PDO-019): A. Shows a hypodense pancreatic head mass with subtle internal arterial phase enhancement (arrow). B. H&E (400X) shows high grade dysplasia characterized by columnar neoplastic cells with eosinophilic cytoplasm. The nuclei overlap, are vesicular with nucleoli, and show loss of polarity and mitoses. C. Organoids were isolated from frozen tissue 33 days post-resection for this high-grade IPMN of pancreatobiliary subtype. Case 4 (MCC-PANC-PDO-022): A. Hypodense mass (arrow) with mild internal enhancement in the pancreatic head. B. H&E (400X) shows moderate grade dysplasia featuring papillary fronds lined by columnar, neoplastic cells, with pseudostratification and goblet cells. The nuclei are elongated and enlarged, with nuclear grooves. Case 5 (MCC-PANC-PDO-0002): A. Images through the pancreatic tail demonstrate diffuse dilatation of the main pancreatic duct (arrow). B. High power showing basally located nuclei. This field shows low grade dysplasia of pancreatobiliary subtype. C. Images taken at day 5. Scale bar, 200mm.