表面骨肉瘤的影像学特征

The distinct roentgenographic features of surface osteosarcomas

目的 结合临床病理表现 ,重点探讨表面骨肉瘤各亚型的影像学特征。方法 对经手术和病理证实的 18例表面骨肉瘤进行回顾性分析。其中经典型皮质旁骨肉瘤 8例 ,去分化皮质旁骨肉瘤 1例 ,骨膜骨肉瘤 5例和高度恶性表面骨肉瘤 4例。重点描述各亚型的影像学表现。结果 8例经典型皮质旁骨肉瘤均未见骨膜反应 ,其中 5例X线呈均一致密的骨性肿块 ,6例肿瘤围绕骨表面生长 ,肿瘤与骨皮质间形成 2～ 3mm透亮的间隙 ;7例CT扫描示肿瘤呈高密度肿块。 1例去分化皮质旁骨肉瘤X线示其内密度不均。 5例骨膜骨肉瘤X线表现为放射状透亮软组织肿块 ,CT见肿瘤内骨小梁呈放射状垂直于骨皮质排列。 4例高度恶性表面骨肉瘤X线呈密度不均一的团块状影 ,CT示肿瘤内有散在不同程度的骨化 ;2例血管造影示区域性血管增多。结论 表面骨肉瘤 4种亚型的各自鲜明的影像学特征有助于早期明确诊断以及制定相应的治疗方案和评估预后 ,尤其是血管造影可以反映去分化皮质旁骨肉瘤和高度恶性表面骨肉瘤的高度恶性特征。

Objective To analysis the distinct roentgenographic features of four subtypes of osteosarcoma arising on the surface of bone. Methods A retrospective review was performed on 18 patients of osteosarcoma arising on the surface of the bone confirmed by surgery and pathology. The patients were diagnosed as 8 cases of conventional parosteal osteosarcoma (c POS), 1 case of dedifferentiated parosteal osteosarcoma (dd POS), 5 periosteal osteosarcoma (PERI) and 4 high grade surface osteosarcoma (HGS) according to the classification system developed at the Mayo Clinic. Results Periosteal new bone formation was noticeably absent in all 8 patients of c POS. On plain roentgenogram,5 of 8 c POS presented as an uniformly dense mass. Six cases had a peculiar tendency to encircle the involved bone with a thin (2～3 mm) lucent zone between the tumor and the underlying cortex. The CT of 7 c POS showed high density osteoid mass. There was largely radioopaque mass with frequent areas of radiolucency on conventional film and CT scan in 1 patient of dd POS. The roentgenographic features of 5 PERI were mixed radiolucent mass on the cortical. The sunburst appearance of radiating spicules of mineralized tumor osteoid at right angles to the cortical bone was seen with CT in all 5 cases of PERI. Four HGS appeared as inhomogeneous mass on roentgenogram. CT detected scattering calcification in the 4 masses and angiography found focal hypervascularity in 2 HGS. Conclusion Four subtypes of surface osteosarcomas have distinct roentgenographic features respectively, which is helpful for diagnosing, treating and predicting outcome of the lesion.