Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, The University of Fukui, Shimoaizuki 23, Matsuoka, Fukui, 910-1193, Japan.
Joint Bone Spine. 2009 Dec;76(6):705-7. doi: 10.1016/j.jbspin.2009.02.009.
A rare case of parosteal aneurysmal bone cyst arising from the humerus in a 7-year-old boy is reported. Plain radiography and CT scanning revealed a marked periosteal reaction and a soft tissue mass surrounded by bone. Erosion of the cortex did not extend to involve the medulla. Three-dimensional CT scanning (3-DCT) revealed a birdcage-like ossified structure that was attached to the cortex of the humerus. 3-DCT was also used to visualize the extent of the tumor and the architecture of the bone, providing important information for planning of surgery. Inside the tumor, there were a number of fluid-fluid levels on T1-weighted MRI and high intensity areas on T2-weighted images. Pathologic examination revealed a central cavity containing a large volume of blood in the tumor and reactive osteogenesis mainly at the marginal regions, and these findings reflected the birdcage-like ossified structure observed by 3-DCT. Pathological examination was required to rule out osteosarcoma in particular, but a diagnosis of parosteal aneurysmal bone cyst was made because of the absence of findings suggestive of malignancy. The tumor was excised en bloc with a clear margin. At 3 years after surgery, there is no evidence of recurrent tumor.
报告一例罕见的发生于 7 岁男孩肱骨的骨旁动脉瘤样骨囊肿。X 线和平扫 CT 显示明显的骨膜反应和由骨包绕的软组织肿块。骨皮质侵蚀并未延伸至骨髓。三维 CT（3-DCT）显示出一个鸟笼样的骨化结构，附着于肱骨的皮质。3-DCT 还用于显示肿瘤的范围和骨的结构，为手术规划提供重要信息。在肿瘤内，T1 加权 MRI 上有多个液-液平面，T2 加权图像上有高信号区。病理检查显示肿瘤中央腔含有大量血液，边缘区主要有反应性成骨，这些发现反映了 3-DCT 观察到的鸟笼样骨化结构。需要进行病理检查以排除骨肉瘤，特别是因为没有提示恶性的发现，因此诊断为骨旁动脉瘤样骨囊肿。肿瘤整块切除，切缘清晰。术后 3 年，无肿瘤复发证据。
