29例头颈部炎性肌纤维母细胞肿瘤的CT及MRI影像学特征分析

CT and MRI features of 29 patients with inflammatory myofibroblastic tumor in the head and neck

目的:探讨头颈部炎性肌纤维母细胞肿瘤(inflammatory myofibroblastic tumor,IMT)的CT及MRI影像学特征,以提高该肿瘤的术前正确诊断。方法:回顾性收集2012年1月-2018年12月上海交通大学医学院附属第九人民医院初诊并经术后病理检查证实的29例头颈部IMT患者,总结分析患者术前CT及MRI影像学表现。结果:29例头颈部IMT患者中,67.0%(20/29)的患者术前被误诊为恶性肿瘤。头颈部IMT的影像学表现多样,局限性软组织内肿块7例,软组织肿块伴邻近骨质破坏12例(颞下窝5例,上颌窦6例,颌面部广泛软组织病变1例),骨内肿块10例(上颌骨5例,下颌骨4例,颞骨1例)。89.7%(26/29)病灶边界不清楚;75.9%(22/29)病灶有骨质破坏,34.5%(10/29)病灶骨质破坏与骨质增生硬化并存。8例患者沿神经孔道侵犯邻近结构(6例发生于颞下窝,其中4例侵犯翼腭窝,沿圆孔、卵圆孔累及颅内,2例侵犯眶尖视神经管;2例发生于下颌骨,侵犯下颌神经管)。头颈部IMT在CT平扫时呈等或稍低密度,未见钙化,增强扫描呈中度至明显强化。在MRI上,9例T1WI呈等或稍低信号;7例T2WI呈低信号;9例DWI呈高信号,ADC值约(0.6~1.0)×10^(-3)mm^(2)/s。TIC曲线Ⅰ型7例,Ⅱ型2例。均未出现颈淋巴结及远处转移。结论:头颈部IMT的影像学特征与恶性肿瘤相近,但骨质破坏的同时伴有骨质增生硬化,T2WI呈低信号,TIC曲线以Ⅰ型为主,极少发生颈淋巴结及远处转移。结合CT、MRI及功能学检查,可在一定程度上反映病灶的组织构成,为术前正确诊断提供重要依据。

PURPOSE:To analyze the imaging features of inflammatory myofibroblastic tumor(IMT) in the head and neck through CT and MRI, and improve the correct diagnosis of the tumor before operation. METHODS:From January 2012 to December 2018, a total of 29 patients with IMT in the head and neck who were initially diagnosed and confirmed by post-operative pathology were retrospectively collected in Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine. Their preoperative CT and MRI findings were analyzed. RESULTS:Of the 29 patients with IMT in the head and neck, 67.0%(20/29) were misdiagnosed as malignant tumors before operation. The imaging findings of IMT in the head and neck were varied, 7 cases were identified as localized soft tissue mass, 12 cases with soft tissue mass and adjacent bone destruction(5 in the infratemporal fossa, 6 in the maxillary sinus, 1 in the wide maxillofacial region), and 10cases with intraosseous mass(5 in the maxilla, 4 in the mandible, 1 in the temporal bone). 89.7%(26/29)were presented as uneven margins. 75.9%(22/29)showed bone destruction, 34.5%(10/29)with hyperostosis and remodeling. Eight cases had a peri-neural infiltration(6 cases occurred in the infratemporal fossa, with 4 cases suffered from invasion through fora-men rotundum and foramen ovale, 2 cases invaded the optic canal, 2 cases occurred in the mandible and invaded the mandibular nerve canal). The IMT in the head and neck showed isodense or slightly hypodense, with no calcification on CT plain scan, and moderate/marked enhancement after contrast-enhanced scanning. MRI showed 9 cases with isointense or hypointense on T1 weighted images, 7 cases with hypointense on T2 weighted images, 9 cases with hyperintense on DWI. The range of ADC value of IMT(9 cases) was about(0.6-1.0)×10^(-3)mm^(2)/s. The TIC type of 7 cases was typeⅠ, and 2 cases with typeⅡ. There were no cervical lymph node metastasis and distant metastasis. CONCLUSIONS:IMT in the head and neck has certain imaging characteristics that are commonly found in malignant tumors. However, IMT in the head and neck can erode and remodel bone, with striped hypointense on T2 weighted image, mostly type I, few cervical lymph node metastasis and distant metastasis. CT, MRI and functional examination can reflect the tissue composition of the lesion to a certain extent, and provide an important basis for the correct preoperative diagnosis.