RESUMEN
Objective: To elucidate the biological behavior of malignant transformation (MT) of fibrous dysplasia (FD) and investigate its risk factors for diagnostic identification. Methods: A retrospective analysis of 394 FD cases from March 2006 to March 2017 in Beijing Ji Shui Tan Hospital was performed. Seven cases had been histopathologically confirmed as malignant (study group). According to age, location, and other epidemiological data, we performed a 1:2 case-matched comparison between the patients with malignant FD and 14 patients with benign disease (control group). Clinical features, visual analog scale (VAS) score, tumor volume, imaging characteris-tics, alkaline phosphatase (AKP) levels, lactate dehydrogenase (LDH) levels, oncologic results, and function data were analyzed. Re-sults: The 7 MT cases included 3 males and 4 females. Mean follow-up time was 175 (3-396) months, and mean and median follow-up time were 25 (3-51) months after MT. Mean and median age were 45.6 and 47 (24-60) years, respectively. Among the 7 cases, 6 in-volved the femur and 1 involved the tibia. Two cases involved a single lesion whereas the remaining 5 involved multiple lesions. There were 5 recurrent cases and 2 initial cases. The mean MT period from initial surgery were 207 (37-377) months. VAS scores in the study group were significantly higher than that in the control group (Z=-3.317, P=0.001); the VAS scores decreased significantly after opera-tion (Z=-2.384, P=0.017). Preoperative AKP levels were different between the study and control group; the levels were significantly higher in the former group than in the latter (Z=2.314, P=0.021). However, postoperative AKP levels were similar in both groups (Z=0.821, P=0.821). LDH levels were not significantly different between the two groups, either preoperatively (Z=1.269, P=0.205) or post-operatively (Z=0.075, P=0.940). As for the study group, AKP levels decreased significantly after surgery (Z=-2.366, P=0.018); LDH levels were also lower after surgery than before (Z=-2.028, P=0.043). CT enhancement values were higher in the study group than in the con-trol group (Z=-3.659, P<0.001). Univariate analysis indicated that preoperative VAS score, AKP level, cortical damage, presence of soft tissue mass, and CT enhancement value were clinical risk factors for determination of MT of FD. Histopathological analysis revealed 4 cases of osteosarcoma, 2 of low-grade spindle cell sarcoma, and 1 of undifferentiated pleomorphic sarcoma. Three patients had re-ceived adjuvant chemotherapy, 2 cases involved pulmonary metastasis, and 1 patient had died. The mean Musculoskeletal Tumor Soci-ety (MSTS) scores for the study and control groups were (95.0±3.9)% and (86.0±10.9)%, respectively (F=5.689, P=0.029). Conclusions:Malignant transformation of fibrous dysplasia is rare. The preoperative VAS score, AKP level, cortical damage, presence of soft tissue mass, and CT enhancement value may be helpful for clinical screening of malignant transformation. An adequate surgical margin is re-quired for treatment of this lesion.
RESUMEN
Objective:To present our experience of the surgical treatment of maxillofacial fibrous dysplasia(FD) using surgical navigation technology.Methods:14 patients with maxillofacial FD were included.Preoperative CT scanning data were obtained and a virtual plan based on the patient's mirrored anatomy was realized.Intraoperatively,a digital reference frame was fixed rigidly to patient's forehead or mandible depending on the location of the lesion.During operation each patient and the virtual image were matched through individual registration technique.A pointing device was constantly used to determine whether the extent of resection was consistent with the preoperative design.The surgical outcome was assessed through fusion of the preoperative planning and postoperative CT reconstruction image.Results:The application of surgical navigation system enhanced the safety and the accuracy of the surgery for the resection of the focal lesion and for the recontour of the profile.There was no complications during 1-3 years follow up.Conclusion:Surgical navigation based on a virtual plan proves to be safe and accurate,and is of great value in managing maxillofacial fibrous dysplasia.