骨韧带状纤维瘤的影像学表现分析(附12例报告)

Imaging features of skeletal desmoplastic fibromas: report of 12 cases

目的探讨骨韧带样纤维瘤的影像学特性,着重研究其MRI信号表现。方法回顾性分析经手术病理证实的12例骨韧带样纤维瘤的放射学和MRI表现。结果本组12例均为单发病灶,四肢管状骨病损7例:骨干3例,干骺端4例;其余脊椎2例,骨盆1例,颅骨1例,跟骨1例。放射学表现:溶骨性破坏11例;溶骨并粗大的骨脊4例,其中2例病变区内见粗细不等、互相交错的“树根”状肿瘤性骨小梁,密度与边缘硬化骨相同;溶骨性改变并有轻微的硬化边3例;皮质突破占2例。病变的平均大小8.1cm×3.9cm(纵向和横断位);2人合并病理性骨折(尺骨、椎体)。在9例行MRI检查的病例中,T1像上均显示病变区域的信号强度与周围肌肉对比呈等信号或略低信号;在T2像上有8例病变组织大部分信号与周围肌肉相等或略低,高信号区域面积均超过病变部分面积的75%(从各层面测量),另外一例(尺骨)病变区域是大部分呈高信号,并合并有病理性骨折。MRI和放射学表现在骨内病变的范围是一致的。结论长骨干骺端为本病好发部位,以溶解膨胀性骨破坏表现为主,X线上病变区域内“树根”状、“根须”状肿瘤性骨小梁形成具有一定特征性,T2WI呈显著低信号(区域面积超过75%)的非成骨性(纤维性)的骨损害表现具有诊断和鉴别诊断意义。

Objective To evaluate the imaging features of desmoplastic fibroma of the bone, with an emphasis on MRI signal characteristics. Methods Images of twelve patients with desmoplastic fibromas proved by pathology were retrospectively reviewed. Results Based on available imaging, there were 7 lesions within the tubular bones： three were diaphyseal, four metaphyseal and epiphyseal. The others in the remaining was the vertebrae （n=2）, calcaneus （n= 1）, pelvis （n= 1）, and skull （n=1）. Radiographs showed the matrix was osteolytic in 11 lesions, osteolytic with coarsened ridge-like trabeculae in 4 lesions, in 2 diseased regions among the 4 lesions present mutually staggered ＂tree root＂ shape tumor bone with the density similarly to the sclerotic rim; mixed lytic and mildly sclerotic in 3 lesions; and mixed lytic and mildly sclerotic in 3 lesions. Cortical breaching was present in 2 lesions. The average size of the lesions was 8.1 cm× 3.9 cm in greatest longitudinal and transverse dimensions. Two patients had evidence of pathologic fracture. In all cases with MRI, T1-weighted sequences showed that the signal intensities within the lesions were isointense or hypointense to adjacent normal muscle. In eight lesions with short T2, at least in part isointense or hypointense to muscle, the low signal encompassed more than 75 % of the tumor, and the other case in which the lesion did not contain main areas of low T2 signal and was confounded by the presence of an associated pathologic fracture. There was no significant discordance between radiographic and MRI images in the intraosseous extent of the tumor. Conclusion Desmoplastic fibromas of long bones are nearly always metaphyseal. Radiographs disclose a expansile lyric lesion with a sclerotic rim and a trabeculated apperance into it. And the ＂tree root＂ or ＂root hair＂ sign is fairly characteristic for this tumor. No calcification and periosteal reaction can be seen. MRI images with T2-weighted sequences were available for review, the most common signal of the lesion was low, occupying more than 75 % of the lesion. The radiologic features of a predominantly osteolytic lesion with prominent T2 shortening on MRI images make a diagnosis of intraosseous desmoid plausible.