OR16 - Prevalence of Nonendodontic Diagnoses in Periapical Biopsies: A 6-year Institutional Experience

Abstract: The purpose of this study was to perform a comprehensive review of periapical biopsies to determine the prevalence of non-endodontic diagnoses in lesions mimicking endodontic pathosis. A retrospective analysis of periapical biopsies submitted to the Texas A&M College of Dentistry’s oral pathology service from 2015 to 2020 was conducted. Search terms were utilized to identify all periapical submissions with endodontic clinical diagnoses. Data points collected included patient demographic information, biopsy site/location, clinical or provisional diagnosis, microscopic description, and final histopathologic diagnoses. Intraoral photos and radiographs were also reviewed when available. Among 6805 endodontic submissions, 278 (4.1%) were histopathologically diagnosed as non-endodontic periapical lesions (NPLs). The most frequent NPL diagnoses were odontogenic keratocyst (n=85, 30.6%), cemento-osseous dysplasia (n=27;9.7%), and dentigerous cyst (n=22; 7.9%). The most commonly encountered malignant diagnoses included squamous cell carcinoma (n=4 ; 0.6%) and multiple myleoma (n= 2; 0.3%). Of the 6489 submissions with endodontic histological diagnoses, the prevalence of periapical granulomas and apical periodontal cysts was 59.6% (n=3865) and 35.7% (n=2315), respectively. Overall, this study aims to alert clinicians to the possibility of discrepant clinical and histologic diagnoses in periapical lesions, thereby emphasizing the importance of careful clinicoradiographic correlation and tissue submission.