Characteristic radiological and histological patterns of jaw fibrous dysplasia and ossifying fibroma.
OBJECTIVE: To document the characteristic histopathological and radiographical patterns of two common FOLs of the jaw bone: the ossifying fibroma (OF) and fibrous dysplasia (FD). Study Design: A retrospective and prospective audit involving histopathologic and radiographic analysis of archival and any new material with full clinical record documentation. Setting: University of Nairobi Dental Teaching Hospital (UNDH), School of Dental Sciences. Study Population. All cases of fibro-osseous lesions diagnosed as FD and OF were retrieved from the files of the UNDH, Division of Oral Pathology and Oral Medicine over a IS-year period and new cases were included as they presented over a 6- month period. Methodology: The case reports ofFOLs diagnosed as FD and OF were retrieved from the records of the UNDH, Division of Oral Pathology and Oral Medicine. Information regarding lesions diagnosed as FD and OF was ana lysed according to location, demographic and radiographic features. For all those cases identified, their paraffin embedded tissue blocks were retrieved from the archives. Slides were prepared from each block retrieved and stained according to the Haematoxylin and Eosin technique for histopathological verification. Available radiographs were analysed as to location of the lesions in the jaws and patterns of radiographic appearance. Data were entered into a computer software and statistical analysis done by using the SPSS Programme, version-l O. Comparison between pathological parameters and final diagnosis was evaluated with the chisquare test. Results: Among the 149 cases of FOLs retrieved for evaluation, two cases affected both the maxilla and mandible and were removed from the evaluation. FD lesions constituted 40 (27.2 %) while 107 (72.8 %) were those of OF. The age ranged from 1-72 years and the median age was 20 years. The mean age was 24.19 years and the standard deviation was 13 years. The male to female ratio was 1: 1.9. Although a higher proportion of females were affected by OF compared to males, the differences were not statistically significant. FD was found to occur in the 1st to the 6th decades of life with the 2nd and 3rd decades mostly affected which was remarkably similar to the pattern of occurrence of OF.