Fibrous dysplasia: clinicopathologic presentation of 36 cases

Objective: Fibrous dysplasia is a slowly progressing bone lesion resulting from displacement of the normal medullary bone with abnormal fibroosseous tissue. The aim of this study was to assess the similarities and differences of our cases in relation to published reports. Material and Method: In this study, the archives of the Uludag University Medical Faculty Department of Pathology were screened for fibrous dysplasia cases between 2004 and 2016. Results: Within the mentioned period, there were 36 cases diagnosed as fibrous dysplasia. There were 21 male, and 15 female cases with an average age of 27.8±14.8 years (range 7-79 years). The most frequently affected sites were femur, costae, and craniofacial bones. There was one case localized to metacarpal bone, a very rare affection site. There were 4 polyostotic cases including 2 cases of McCune-Albright syndrome. Pelvic bone was affected in the polyostotic type, similar to published reports. Unlike former reports, however, long tubular bones were affected in male patients in our series. In our series, 32 cases had classical fibrous dysplasia, 3 cases had fibrocartilaginous, and one case had fibroosseous variants. Four cases localized to costae were accompanied by aneurysmal bone cyst. The presenting symptom was pathological fractures in a total of 4 cases, 3 localized to the femur, and 1 to the costa. Recurrence occurred in 5 cases treated with curettage. Two of the monostotic fibrous dysplasia cases developed malignant transformation into osteosarcoma. Conclusion: We conclude that our series of fibrous dysplasia cases have slight differences and mainly similar characteristics with the series reported earlier, when all features are taken into consideration.