骨原发神经鞘瘤的临床病理分析

Clinicopathologic charististics of primary Schwannoma of the bone

目的报告4例罕见的骨原发神经鞘瘤，探讨其诊断标准以及与软组织神经鞘瘤在形态学上的差异。方法复查2002至2013年本院诊断的所有骨相关性神经源性肿瘤，从中筛选出4例由长骨和扁骨髓内发生的骨原发神经鞘瘤，收集其临床及影像学资料，通过光镜观察及免疫组织化学EnVision法分析其临床、影像学、病理学特征、免疫表型及病理鉴别诊断。结果4例均具有神经鞘瘤的典型形态学改变和免疫表型，与软组织神经鞘瘤相比，骨原发神经鞘瘤在形态学上有以下特征：影像学呈良性表现，低倍镜下肿瘤缺乏包膜，局部浸润骨组织或破坏骨皮质，偶可累及骨旁软组织，肿瘤大多为实性，较少囊性变，常以AntoniA区结构为主，部分区域富于细胞。结论骨原发神经鞘瘤非常罕见，发生于长骨和扁骨髓内，由于其病理形态和生长方式与其他部位神经鞘瘤有一定的差异，应注意避免将其误诊为骨原发低度恶性梭形细胞肉瘤而导致不必要的过度治疗。

Objective To evaluate the diagnostic criteria and morphologic difference of primary schwannoma from that of soft tissue schwannoma. Methods All neurogenic tumors of the bone in this hospital from 2002 to 2013 were reviewed, four cases of primary schwannoma arising from bone were selected. Their clinical features, radiologic appearance and pathologic findings were evaluated. Immunophenotyping was performed using EnVision method. Results All four cases had classic morphologic features and immunophenotype of conventional schwannoma. Compared with sehwannoma of the soft tissue, primary bone schwannoma had the following features： benign radiological appearance, absence of capsule under light microscope, local infiltration of bone or destruction of bone cortex, occasionally involving extraosseous soft tissue. Most tumors were solid, with less cystic degeneration. Histologically, the tumors were mainly composed of compact areas of spindle cells （Antoni A） , and areas of hypercellularity could often be observed. Conclusions Primary schwannoma of the bone is rare, usually arises within the long bones and flat bones. Compared to conventional soft tissue schwannoma, it shows different growth pattern, imaging and pathologic features; thus care should be exercised not to misdiagnose schwannoma of the bone as other primary low-grade malignant spindle cell sarcoma of the bone and to avoid unnecessary over-treatment.