Author’s Disclosure Block: Steffie Arès, none; Charlotte Lussier, none; Olivia Serhan, none; Myriam Belaiche, none; Patrick Daigle, none; Erika Massicotte, none; Patrick Boulos, none; François Codère, No conflict of interest; Evan Kalin-Hajdu, none

Abstract Body
Purpose: Primary acquired nasolacrimal duct obstruction (PANDO) is rare in patients <50 years of age. For this reason, approximately 50% of ASOPRS surgeons obtain imaging in all young patients prior to dacryocystorhinostomy (DCR).1 However, no study has indirectly (via pathology) or directly (via imaging) investigated the validity of this practice. The primary objective of this study was to investigate whether pre-DCR imaging is justified in young patients with presumed PANDO. Study Design: Retrospective cohort study Methods: A retrospective chart review was conducted at the University of Montreal on consecutive patients that underwent DCR for clinically presumed PANDO from 2014 to 2024. Results: 851 sides of 768 patients were diagnosed with PANDO prior to DCR. 410 of these 851 cases (48.2%) had a lacrimal sac biopsy during DCR (surgeon's routine practice or due to an abnormal appearing sac). 54 cases were≤50 years of age (group 1), whereas 356 were > 50 years of age (group 2).49 of 54 (90.7%) cases in group 1 had expected lacrimal sac pathology (non-specific inflammation), compared to 314 of 356 (88.2%) in group 2. Regarding unexpected pathologies, 0 were malignant or of malignant potential in group 1, compared to 15 (4.21%) in group 2. Logistic regression analysis demonstrated that age was neither a predictor of unsuspected pathology (B=-0.01, p = 0.99) nor a predictor of unsuspected malignancy (B=0.00, p=1.00).Pre-DCR imaging (CT or MRI) was obtained (surgeon’s routine practice) in 98 of 851 patients (11.5%). In no case did imaging yield unexpected results (evidence of malignancy, erosive process, etc.). In 1 case, despite normal imaging, pathology revealed an unsuspected lacrimal sac malignancy. Conclusion: Young age does not appear to increase the odds of encountering an unexpected pathology during DCR. Despite the popularity of the practice, evidence does not substantiate preferentially imaging young patients with PANDO prior to DCR.