非骨化性纤维瘤的影像学诊断

Imaging diagnosis of non-ossifying fibroma

目的探讨非骨化性纤维瘤的影像学诊断价值。方法回顾性分析经手术病理证实的20例非骨化性纤维瘤的影像学资料,20例均行X线平片检查,CT检查12例,MR检查1例。结果19例病灶位于长管骨,包括胫骨11例,股骨6例,肱骨2例,另1例位于肋骨;干骺端11例,骨干5例,骨端4例。按影像学表现分为两型:皮质型(或偏心型)14例,髓腔型(或中央型)6例。皮质型病灶位于骨皮质内或骨皮质下,X线平片、CT表现为皮质内或皮质下的单房状(10例)或多房状(4例)偏心性骨质破坏区,伴有轻度膨胀,灶内可见纤细的残留骨嵴,病灶周围有清楚的硬化边,以髓腔侧明显。髓腔型病灶位于骨髓腔,X线平片、CT表现为呈中心性扩张的类圆形或椭圆形骨质破坏区,有薄层硬化边,可伴有轻微膨胀,骨皮质变薄。1例皮质型病灶MRI表现为T1WI呈稍低信号,T2WI呈高信号,增强扫描病灶明显强化。结论非骨化性纤维瘤在病理学上与纤维性骨皮质缺损相似,但影像学特征不同,明确的影像学诊断能为临床治疗提供依据。典型病例单凭X线平片即可诊断;CT较X线平片更清楚显示病灶在骨内的位置,灶内及周围骨结构的详细情况,对明确诊断起重要作用;MRI显示软组织及骨髓优于CT,能帮助对个别病例的鉴别诊断。

Objective To evaluate the imaging diagnosis of non-ossifying fibroma. Methods Images of 20 patients with non-ossifying fibroma proved by operation and pathology were retrospectively analyzed. X-ray plane films and CT images were obtained in all 20 cases and 12 cases, respectively,and MRI was performed in 1 case. Results The lesions occurred in long bone in 19 cases,including tibia （11 cases ） ,femur （6 cases） ,and humerus（2 cases）. In the rest 1 case, the lesion was found at rib. The lesions were located at metaphysis in 11 cases, at diaphysis in 5 cases, and at bone end in 4 cases. Classified with the imaging findings, the lesions belonged to two types： cortical （eccentric） type and medullar （central） type. In 14 cases of cortical type, the lesions were located within or beneath the cortex. X-ray and CT showed unilocular （10 cases） or multiocular （4 cases） bone destruction areas eccentrically expansive and residual osseohs tissue was seen within the lesions, the lesions had a clear sclerotic margin, which was more obvious at the marrow side. Medullar type was seen in 6 cases, in which the lesions were located at the center of the bone. X-ray and CT showed round or oval, slightly centrally expansive bone destruction areas, where the lesions had a sclerotic margin and the cortex involved was thinned. In the case in which MRI was performed, the lesion was hypointense on T1WI, hyperintense on T2WI, intensively enhanced during the contrast enhanced scan. Conclusion Non-ossifying fibroma has similar pathological nature with fibrous cortical defect, while both entities are different on the imaging. A definite imaging diagnosis provides guidance for clinical management. Typical lesions will be diagnosed simply with X-ray plain along.. CT is superior to X-ray plain film in demonstrating the details of the lesion, the location, the internal structure and the adjacent bone. CT plays an important role in definitive diagnosis. MRI is the best modality to evaluate soft tissue and the bone marrow, which is helpful for differential diagnosis in some cases.