骨旁骨肉瘤的影像学表现及相关病理改变

Imaging Manifestations and Relevant Pathological Changes of Parosteal Osteosarcoma

目的:探讨骨旁骨肉瘤的影像学表现及与其相关的病理改变。方法:回顾性分析36例经病理证实的骨旁骨肉瘤的影像及病理学资料。结果:女性21例,男性15例,年龄15~56岁,平均36岁。最常见部位为股骨远端(21例),其次为胫骨近端(4例)及肱骨近端(4例)。影像学上主要表现为紧贴骨皮质的宽基底软组织肿块(27例),肿块包绕骨皮质生长(平均值50%-55%),皮质增厚和/或破坏,骨膜反应仅1例,23例可见髓腔浸润。X线摄片(27例)和CT(27例)上肿块呈高密度为主伴局部低密度,MRI(27例).上呈低信号为主混杂信号,MR增强扫描(19例)肿块呈中度至明显强化。6例术前误诊为普通型骨肉瘤。病理提示肿瘤主要由高分化肿瘤性骨和低细胞性纤维间质组成(34例),其中4例有去分化成分。结论:骨旁骨肉瘤影像.上主要表现为起源于长骨干骺端宽基底,包绕骨皮质生长的富肿瘤骨的软组织肿块,镜下主要以纤维骨性成分为主,具有一定特征性。不典型骨旁骨肉瘤需与高级别骨肉瘤鉴别。

Purpose:To investigate the imaging appearance and pathologic changes of parosteal osteosarcoma.Methods:Data of 36 pathologically confirmned parosteal osteosarcomas were retrospectively reviewed.Result:There were 15 male and 21 female patients with an age range of 15--56 years(average age,36 years).The most frequent lesion locations were the posterior aspect of the distal femur(21 patients)followed by the proximal tibia(4 patients)and proximal humerus(4 patients).The imaging of them showed a broad-based sof-tissue mass that was attached to the cortex(27 patients)and showed cortical thickening and/or erosion,marrow invasion(23 patients),but rarely periosteal reaction(only I patient).Sof-tissue masses were often surrounded 50%-55%of the cortex.Lesions commonly showed focal or califlower-like high density at X-ray and CT,rflecting ostcoblastic lesions;and high intensity signal on T2-weighted MR images,rflecting soft-tsse lesions which were moderate or marked enhanced on post-contrast images.Six patients were misdiagnosed as conventional osteosarcoma.Pathological results revealed that all lesions contained mature trabecular bone and fibroblastic spindle cell stroma.Dedifferentiated components were shown in 4 patients.Conclusion:The imaging and pathological manifestations of parosteal ostcosarcoma presents obvious characteristics.But atypical lesion must be differentiated from high-grade osteosarcoma.Comprehensive clinical,pathological and imaging analysis can help to improve the diagnostic accuraey of this lesion.