Conventional and Non-Conventional Dysplasias Associated with Inflammatory Bowel Disease—A Single-Centre Experience

Background: Recent studies have identified multiple subtypes of non-conventional dysplastic lesions associated with inflammatory bowel disease (IBD). This study aimed to characterise and compare all IBD-associated dysplasias and determine their prevalence within a Southern Hungarian population. Methods: A consecutive cohort of IBD patients between 2011 and 2023 was retrospectively analysed. All available hyper- or neoplastic samples were reclassified according to current pathological criteria. Results: In this 13-year retrospective, single-centre, cohort study, 2396 IBD patients were identified, with 176 possessing samples for re-evaluation. Conventional dysplasia was identified in 130 patients (74%), non-conventional dysplasia in 50 patients (28%), and 33 patients were diagnosed with both (19%). Age (OR = 1.06; 95% CI: [1.03–1.09]; p < 0.001) and male gender (OR = 2.63; 95% CI: [1.07–6.45]; p = 0.032) were associated with higher odds of conventional dysplasia, compared with non-conventional dysplasia. Colorectal carcinoma development and M stage were associated with lower odds of conventional dysplasia: OR = 0.17 ([0.06–0.47]; p < 0.001) and OR = 0.05 ([0.01–0.5]; p = 0.006), respectively. Significant associations were observed with macroscopic appearance (p = 0.013), grade (p = 0.002), localisation (p < 0.001), size (p = 0.016), macroscopic morphology (p = 0.004), grade (p < 0.001), histological subtype (p = 0.001), T stage (p = 0.008) and microsatellite status (p = 0.019). Conclusions: Non-conventional dysplasias were identified in a substantial proportion of neoplastic lesions (50/176; 28%) among IBD patients. These findings highlight the importance of thorough histopathological evaluation to confirm complete resection. Patients with IBD-associated dysplasia, particularly non-conventional types, may benefit from intensified surveillance strategies.