Analysis of Clinical Parameters and Histopathological Features of Recurrent and Non Recurrent Odontogenic Keratocysts: A Cohort Study

Introduction: Odontogenic Keratocyst (OKC) accounts for 10- 20% of all odontogenic cysts and is characterised by unique clinical and histological features, along with a high propensity for recurrence of around 25% after enucleation. The literature presents varied findings regarding the clinical and histological features depicting the recurrence potential of OKCs. Aim: To analyse and compare the clinical and histological parameters between recurrent and non recurrent OKCs. Materials and Methods: This cohort study included 53 excised cases of OKC retrieved from January 2021 to December 2023 (three years) with a maximum follow-up of 36 months from the Department of Oral Pathology and Microbiology at Saveetha Dental College and Hospitals, Chennai, Tamil Nadu, India. Cases that included only incisional biopsies and any cases with epithelial dysplasia were excluded. There were 36 non recurrent cases (Group I) and 17 recurrent cases (Group II). Data pertaining to age, gender, site, laterality, radiological findings, specific histological features, treatment and follow-up were retrieved for both groups, tabulated and analysed using IBM Statistical Package for the Social Sciences (SPSS) for Windows, Version 26.0. Independent t-tests and Pearson Chi-square tests were used to analyse the data, with any value <0.05 considered statistically significant. Furthermore, the Kaplan-Meier curve was used to plot disease (recurrence)-free survival, where recurrence was considered as the event. Results: The present study included 36 non recurrent and 17 recurrent OKCs. No statistical difference was found between the means of age (p-value: 0.432), gender (p-value: 0.254), location (p-value: 0.892), laterality (p-value: 0.381) and uni-/ multilocularity (p-value: 0.348) between the recurrent and non recurrent cases. However, histologically, recurrent cases showed significantly more chronic inflammatory reactions in the wall (p-value: <0.001) and a higher percentage of basal budding in the epithelial lining (p-value: 0.001). No significant difference was noted when comparing the incidence of satellite cysts (p-value: 0.259), mitosis (p-value: 0.701), subepithelial split (p-value: 0.362) and juxta-epithelial hyalinisation (p-value: 0.259). A follow-up period ranging from one month to 34 months was noted, which was plotted on the Kaplan-Meier curve and compared with histological features. The cases managed conservatively demonstrated a higher incidence of recurrence. Conclusion: Basal budding and chronic inflammatory reactions are independent histopathological features associated with a higher recurrence potential in OKCs.