儿童头颈部横纹肌肉瘤的CT及MR影像学特点

CT and MR imaging characteristics of head and neck rhabdomyosarcoma in children

目的探讨儿童头颈部横纹肌肉瘤(rhabdomyosarcoma,RMS)的CT及MR影像学特点。方法回顾性分析29例病理证实的儿童头颈部RMS的影像学资料,其中23例行MRI检查,18例行CT检查。结果 10例发病部位位于鼻咽部,4例位于鼻腔及鼻窦,5例位于鼻翼部,3例位于颌面部,6例位于耳部,1例位于左侧颞下窝。肿瘤形态不规则,呈浸润性生长,多侵蚀破坏邻近骨质。CT图像病灶密度不均匀,瘤体内均无钙化。MR检查T1WI呈等或稍低信号,T2WI呈稍高信号,信号不均匀,增强后瘤灶明显不均匀强化。8例侵犯眼眶,13例进入并侵犯鼻腔,14例侵犯副鼻窦,15例侵犯颞骨乳突,12例侵犯颞骨岩部,14例突破颅底,累及硬脑膜,同时4例侵犯邻近脑组织,2例发生脑脊液转移。结论儿童头颈部RMS好发于脑膜旁区。CT能够很好地显示肿瘤对周围骨质结构的破坏,而MR能更清楚显示肿瘤软组织受累范围,两者结合可提供更全面的影像信息。

Objective To explore CT and MR imaging features of head and neck rhabdomyosarcoma in children.Methods Twenty-nine pediatric patients with head and neck rhabdomyosarcoma were retrospectively analyzed. Twenty-three of these cases underwent MRI examination and 18 received CT scanning. Results Among the 29 cases,tumors originated in the paranasopharynx（ n = 10）,nasal cavity and paranasal sinuses（ n = 4）,nose（ n = 5）,cheek（ n = 3）,ear（ n = 7）,and left fossae infratemporalis（ n =1）. The tumors were irregular and inhomogeneous in density,without any calcification. On MRI images,the tumors were isointense to muscle or slightly hypointense to muscle on T1 WI,and hyperintense to muscle on T2 WI. Post-contrast MR showed intense inhomogeneous enhancement. The tumors grew infiltratively and eroded the adjacent bone. The lesions invaded the orbit,nasal cavity,paranasal sinuses,mastoid,petrous bone,and skull base in 8,13,14,15,21,and 14 cases respectively. The lesions invaded the adjacent brain in 4 cases. Cerebrospinal fluid metastasis was proved in 2 cases. Conclusions Head and neck rhabdomyosarcoma in children occurs mostly in the parameningeal region. CT can provide a clear view of bone destruction while MRI can demonstrate optimally the extent of lesion invasion. Combined imaging commodities can provide more detailed information for diagnosis and therapy of rhabdomyosarcoma.