骨巨细胞瘤继发动脉瘤样骨囊肿的影像诊断

Imaging diagnosis of aneurysmal bone cyst secondary to giant cell tumor

目的通过对骨巨细胞瘤(GCT)继发动脉瘤样骨囊肿(ABC)的各种影像表现的深入分析,提高其诊断符合率。方法对25例经病理证实的GCT继发ABC的X线、CT及磁共振成像(MRI)资料进行综合分析,评估病灶的发病部位、骨质破坏类型、有无软组织肿块、有无液-液平面、强化特点等。结果 25例中19例均发生于长管状骨,6例位于不规则骨。25例X线表现为囊状膨胀性骨质破坏,20例为中心性骨质破坏,5例为偏心性骨质破坏;其中有5例出现软组织肿块,骨包壳欠完整;3例出现骨性分隔,1例有明显硬化边;1例伴有病理性骨折及骨膜反应。25例患者CT均呈不同程度的囊状膨胀性溶骨性骨质破坏,11例偏心性骨质破坏,14例为中心性骨质破坏。9例骨皮质断裂,其中有4例边缘呈分叶状,出现软组织肿块;11例病灶内可见分隔或骨嵴,其中5例可见液-液平面。25例患者MRI均表现为不同程度的膨胀性骨质破坏,21例病灶边缘呈分叶状,在T1WI及T2WI上可见病灶边缘有完整或不完整的低信号环。6例出现软组织肿块或周围组织水肿,4例软组织肿块突破骨皮质,T1WI上为不均匀低/等信号,T2WI为混杂稍高/高信号。11例可见低信号分隔,21例见多个液-液平面形成。增强扫描可见肿瘤实性成分中度或高度强化,囊性成分不强化,囊壁及分隔明显强化。结论影像诊断怀疑单纯性GCT或ABC的病灶内见到液-液平面,要考虑到继发ABC的可能。

Objective To improve recognition andimaging diagnosis of aneurysmal bone cyst secondary to giant cell tumor by intensively investigating the imaging features demonstrated by imaging manifestations. Methods To collect the dates 25 patients with aneurysmal bone cyst secondary to giant cell tumor were proved by operation and pathology from analyzed and summarized their imaging manifestations and correlation with pathohistology. Results Nineteen lesions were located in epiphysis and metaphysic regions of long bone.Six lesions were located in irregular bone.All cases showed a cystic lession with expanded and osteolytic,eccenteic 20 cases and centric 5 cases.Five cases of them emerged soft-tissue masses, bone cladding was incomplete. Three cases displayed trabeculate, the margin was well define with a rim of bone sclerosis in l case. One case with pathological fractures and periosteal reaction. All cases CT showed a cystic lession with expanded and osteolytic,eccenteic 11 cases and centric 14 cases.Nine cases Cortical bone fracture and soft tissue mass in 4 cases. Eleven cases displayed trabeculate,the sign of muhiplanar fluid- fluid level was present in 5 patients. Magnetic resonance imaging（MRI） scans were available in 25 patients.All case showed cystic, dilated lesions with solid areas. Twenty-one cases showed sublobe margin,with complete or incomplete hypointensity ring on T1WI and T2WI. Six cases emerged soft-tissue masses or tissue oedema aroundnidus. Four casesshowed uneven low or equisignal signal on T1WI,mix slightly high or high signal on T2WI. Eleven cases showed septa- tions or cristae in the lesions,21 cases showed multiplanar fluid-fluid level.The solid areas and cystic-wall of lesions showed contrast enhancement in all patients. Conclusion We must consider the possibility of secondary ABC when imaging diagnosis of simple giant cell tumor or aneurysmal bone cyst within fluid-fluid level.