Clinicopathological characterization of 2,238 endodontic and nonendodontic periapical lesions

To determine the clinicopathological features of 2,238 endodontic and non-endodontic periapical lesions (PLs) retrieved from a database of an oral and maxillofacial pathology laboratory.

This retrospective cross-sectional study analyzed 12,441 histopathological records registered between 1956 and 2019. Of these, 2,238 cases diagnosed as PLs were selected. The lesions were classified as endodontic or non-endodontic, and clinicopathological variables, including microscopic diagnosis, sex, age, anatomical location, and lesion size, were evaluated.

During the study period, the laboratory recorded 12,441 lesions, of which 2,238 (18%) were PLs. Most lesions were of endodontic origin (2,073; 92.6%), whereas non-endodontic PLs accounted for 165 cases (7.4%). Among the non-endodontic lesions, odontogenic cysts were the most frequent (54.1%), followed by non-odontogenic cysts (14.3%). Malignant neoplasms comprised 2.3% of non-endodontic lesions and 0.2% of all PLs. Radicular cysts were the most common diagnosis (977; 47.1%), followed by periapical granulomas (827; 39.9%) and residual cysts (113; 5.4%). Most endodontic lesions measured less than 2 cm, although residual cysts were significantly larger. Non-endodontic PLs mainly included odontogenic keratocysts, nasopalatine duct cysts, and unicystic ameloblastomas, which showed a predominance in the mandible and larger dimensions. Overall, PLs were more frequent in women (mean age: 36.6 years) and predominantly affected the anterior maxilla.

Most of the 2,238 biopsy-confirmed PLs identified over 63 years were of endodontic origin, whereas a small proportion comprised non-endodontic and malignant lesions mimicking endodontic disease. Histopathological examination may be particularly important for persistent, enlarging, surgically treated, or clinically and/or radiographically atypical lesions.

This study demonstrates that although endodontic lesions predominate, non-endodontic, uncommon, and malignant lesions may mimic endodontic disease. Persistent, enlarging, surgically treated, or atypical periapical lesions warrant careful evaluation. Histopathological examination can establish a definitive diagnosis in selected cases and identify lesions that might otherwise be clinically or radiographically misclassified.