IntroductionBranch-Duct intraductal papillary mucinous neoplasms (BD-IPMNs) are becoming more prevalent with advanced medical imaging, and account for the majority of pancreatic cystic neoplasms (PCNs). Most incidental lesions should be surveyed, with resection reserved for specific, high-risk cases. Solid organ transplantation candidates maybe high risk for resection prior to transplant, and will require systemic immunosuppression after transplant, which has been theorized to alter the natural history of the IPMN. We aim to describe the of progression in surveilled cysts after solid organ transplantation. MethodsA prospectively maintained database of pancreatic cystic neoplasms was queried for patients with IPMN. Patients who had received a previous solid organ transplantation and with >2 imaging studies >6 months apart after transplantation were included. Clinically relevant progression (CR-Progression) was defined as symptoms, worrisome/high-risk stigmata, or invasive cancer (IC). Growth >5mm in 2 years is considered CR-Progression; size>3cm alone is not. ResultsBetween 1997-2023, 252 patients received solid organ transplantation (liver=86, kidney=113, and lung=54) and were diagnosed with an IPMN. This cohort was compared to a set of 770 patients surveilled for IPMN who did not have previous transplantation. Median follow-up period was 3.7 years (IQR 1.6-6.8).Two transplant patients (0.8%) developed IC, and four (1.6%) high-grade dysplasia. Both were less common in transplant patients than the non-transplant population (IC=3.3%, HGD=2.9%), though this was not significant on time-to-event analysis (IC p=0.152, HGD p=0.352).The rate of CR-progression was high in the transplant cohort (n=118, 47%). Features of CR-progression included size growth (n=79, 67%), other worrisome/high-risk stigmata (n=25, 21%), new main duct involvement (n=14, 12%). Compared with the non-transplant (n=128, 17%), transplant patients had a higher rate of CR-progression (p<0.001), which was mostly explained by a more frequent size growth (31% vs 9%, p<0.001). However, no transplant patients with size growth CR-progression developed IC.Seventeen (6.7%) required pancreatic surgery for CR-progression after transplant versus 58 (7.5%) in the non-transplant population. Six (35%) resected cysts harbored high-risk pathology after transplant (IC=2, HGD=4), versus 40 (69%) in the general population (p<0.001, IC=29, HGD=11) ConclusionsMalignant transformation of BD-IPMNs is rare despite systemic immunosuppression in solid organ transplant patients. This supports transplantation in patients with IPMN without fear of worsening their risk of pancreatic cancer, although it was associated with a higher risk of disease progression. Patients with IPMNs should be surveilled with yearly scans after transplant, with pancreatic resection reserved for only high-risk features as we continue to define the optimal criteria for those with CR-progression.