鼻咽癌放疗诱发骨肉瘤的影像学分析

The Imaging Analysis of Osteosarcoma Induced by Nasopharyngeal Carcinoma Radiation

目的探讨鼻咽癌放疗诱发骨肉瘤的影像表现,并复习相关文献,以期对其进一步认识。资料与方法回顾性分析4例经病理证实的继发于鼻咽癌放疗的骨肉瘤患者的影像资料,4例均行CT平扫,3例行增强扫描,1例行MRI平扫及增强扫描。结果病变位于上颌骨、下颌骨、颈部软组织及鼻腔各1例。CT像上4例均见软组织肿块包绕大小不等的高密度瘤骨,3例与周围组织分界不清且均有邻近骨质破坏,另1例有包膜与周围组织分界清晰;增强扫描3例,1例包膜环形强化,3例软组织肿块不均匀轻度强化,中央坏死区无强化;MRI表现为1例T1WI、T2WI均为混杂信号,中央瘤骨为低信号,增强扫描,病灶不均匀明显强化。病理表现为2例来源于颌骨,软骨母细胞型及纤维母细胞型各1例,1例考虑为来源于软组织骨软骨瘤放疗后软骨母细胞型骨肉瘤,1例为来源于鼻腔纤维母细胞型骨肉瘤。结论瘤骨为鼻咽癌放疗诱发骨肉瘤的主要特征表现,结合临床与影像学检查,可提高对该病的诊断水平。

Objective To discuss the imaging appearances of nasopharyngeal carcinoma radiation-induced osteosarcoma,in order to achieve more recognition about the disease.Materials and Methods The imaging appearances of 4 cases with nasopharyngeal carcinoma radiation-induced osteosarcoma confirmed by operation and pathology were reviewed retrospectively.All had the CT scan,3 cases with enhanced CT scan and 1 case with MRI.Results Among 4 cases of radiation-induced osteosarcoma,tumors were located in maxillary,mandible,the neck soft tissue and ethmoid 1 case respectively.On CT images,all the lesions appeared the soft-tissue mass surrounding the high-density tumor bone,1 case enveloped with a clear delineation of the surrounding tissue,others were unclear,and with the adjacent bone destruction.2 cases were enhanced with hypodensity in the necrotic area and 1 case with the circular enhancement.On MRI images,1 case showed heterogeneous intensity signal on T1WI and T2WI,the tumor bone showed hypointensity signal both on T1WI and T2WI.Lesions were significantly enhanced.Two cases were from jaw,there was chondroblastic osteosarcoma and fibroblast cell osteosarcoma in 1 case respectively.1 case was from the source of soft tissue osteochondroma after radiotherapy chondroblastic osteosarcoma,and the other from ethmoid sinus and nasal fibroblast cell osteosarcoma.Conclusion The bone tumor is the main feature of nasopharyngeal carcinoma radiation-induced osteosarcoma,combining the clinical history with imaging can helpful the diagnosis of the disease.