实性动脉瘤样骨囊肿的影像学表现

Imaging Findings of Solid Variant of Aneurysmal Bone Cyst

目的探讨实性动脉瘤样骨囊肿的影像学表现,提高本病的鉴别诊断能力。资料与方法回顾性分析2007年1月—2019年1月空军军医大学西京医院经术后病理证实的5例实性动脉瘤样骨囊肿的X线、CT、MRI资料,分析病灶所在母骨位置、病灶大小形态、边缘、肿瘤基质和周围软组织改变等影像学征象。结果5例均为女性,病灶发生于胫骨2例、股骨1例、寰椎椎弓1例、髋臼周围1例,均偏心性位于母骨。病灶大小4.0~17.0 cm,均为大片状地图样、溶骨性破坏,膨胀性较轻。病灶边界清晰3例、模糊2例,有窄且长短不等的硬化缘。所有病灶骨皮质变薄、壳样改变,局部断裂、筛孔状改变或大段缺失。1例周围有软组织肿块。所有病变均无骨膜反应。2例病灶周围广泛水肿。CT表现:2例病灶内部呈等或略低于肌肉密度,无基质矿化。MRI表现:2例病灶内部T1WI信号略高于肌肉,T2WI呈均匀高信号,且有点状更高信号。所有病例均无病理性骨折。结论实性动脉瘤样骨囊肿青年女性好发。病灶呈轻度膨胀性、溶骨性改变,有窄硬化缘,CT呈均匀等低密度,MRI呈混杂信号,可突破骨皮质形成软组织肿块,邻近骨髓与软组织明显水肿。

Purpose To investigate the imaging findings of solid variant of aneurysmal bone cyst,and to improve the ability of radiologists in the differential diagnosis of the disease.Materials and Methods Five cases with solid variant of aneurysmal bone cyst confirmed by pathology in Xijing Hospital,Air Force Medical University from January 2007 to January 2019 were retrospectively collected,and X-ray,CT,MRI imaging data of all cases were summarized and reviewed.The imaging signs,including the involved maternal bone,lesion position,lesion size and shape,margin,tumor stroma,and soft tissue mass were summarized and analyzed.Results All 5 patients were female.The involved bones were tibia(n=2),femur(n=1),cervical vertebral arch(n=1)and acetabulum(n=1).All 5 lesions were eccentric tumor.The lesion diameter ranged from 4.0 to 17.0 cm.All lesions showed large map-like osteolytic destruction with less expansive.There were 3 cases with clear boundary and 2 cases with blurred margin.All cases had varying degrees of bone cortical thinning,shell-like changes,regional fracture,ethmoidal changes or large segment loss.Soft tissue mass occurred in 1 case.No periosteal reaction was found in all lesions.Two lesions showed extensive edema around the lesions.There were 2 cases with iso-or slightly lower density compared with muscle CT value without matrix mineralization on CT imaging.There were 2 cases with slightly higher than the muscle signal on T1WI and heterogeneous signal as well as high intensity spots on T2WI.No pathological fracture was found.Conclusion Solid aneurysmal bone cysts are more common among young women.The lesions shows mildly expansive and osteolytic changes with sclerotic and narrow margins.CT shows homogeneous iso-density or low density,MRI shows mixed signal.Lesion can break through the bone cortex to form soft tissue mass and edema and to involve the adjacent bone marrow.