Peritrabecular clefting in differentiating ossifying fibroma from fibrous dysplasia of the jaws

Context: Fibrous dysplasia (FD) and ossifying fibroma (OF) are the most prevalent fibro-osseous lesions in Nigerians and present with overlapping clinical, radiological, and microscopic features, resulting in diagnostic challenges for the pathologist and surgeon. Aims: The objectives of this study were to differentiate between FD and OF using clinical features, radiographic features, growth rate, and microscopic method to evaluate the prevalence of peritrabecular clefting. Settings and Design: Random sampling was used to select the sample size of 30 for each lesion from cases diagnosed from 1994 to 2014 in the oral biopsy service of Lagos University Teaching Hospital. Subjects and Methods: Hematoxylin and Eosin sections were prepared from retrieved blocks of FD and OF which had been blinded. Each section was divided into four quadrants, largest vertical and horizontal dimensions of cleft surrounding five trabeculae in each quadrant were measured with ocular grid and multiplied to project an estimation of area of each cleft. Data retrieved on clinical and radiographic information were statistically compared to differentiate between the lesions. Statistical Analysis Used: Statistical Package for the Social Sciences for Windows (version 16.0, Chicago, IL, USA) was used. Results: In the study, 77% of FD had clefts, none was seen in OF. This difference was statistically significant P = 0.001. Ill-defined radiographic borders occurred in 60% of FD, well-defined borders occurred in 81% of OF. In lesions with mixed radiolucency and radiopacity, an association was established between border definition and type of lesion. P = 0.02122. Conclusions: Peritrabecular clefting was observed in 77% of FD, while this feature was not observed in OF and could therefore serve as a reliable parameter to differentiate the lesions.