骨炎症性肌纤维母细胞瘤的临床及病理学特点

Inflammatory myoflbroblastoma tumor of the bone

目的 探讨骨炎症性肌纤维母细胞瘤(IMTB)的临床病理特点、诊断及鉴别诊断。方法 对2例骨炎症性肌纤维母细胞瘤进行临床和病理(HE染色、免疫组化、特殊染色和电镜)观察,复习有关文献,进行对比分析。结果 肿瘤1例发生在左胫骨中上段髓腔内,另1例在耻骨及坐骨髓腔内。2例都侵犯骨皮质,其中1例侵及邻近软组织。2例组织学改变:肿瘤细胞排列呈编织状、束状,部分杂乱无章;细胞呈长梭形,有红染的胞浆,异型性不明显,核分裂较少。肿瘤组织中有淋巴细胞、浆细胞浸润。免疫表型:Vimen-tin、Desmin、actin和SMA瘤细胞呈阳性表达。电镜:肿瘤细胞的胞质内可见密体和密斑的肌丝束,胞质内还可见较多的粗面内质网及合成的胶原前体,细胞外基质中见多量的胶原纤维。结论 骨炎症性肌纤维母细胞瘤是一种罕见的肿瘤,异型性不明显,在诊断上应与纤维肉瘤、恶性纤维组织细胞瘤、平滑肌肉瘤、韧带状纤维瘤相鉴别。

Objective To investigate the pathological features of inflammatory myofibroblastic tumor of the bone (IMTB) , its diagnosis and differential diagnosis. Methods Two cases of IMTB were analyzed clinically and pathologically by using HE staining, immunohistochemical assay, specific staining and electric microscope. The literature review and comparative analysis were done at the same time. Results The tumor occurred in the upper shaft of left tibia of 1 case, and in the pubis and ischium of another case. Bone - cortex in both cases was damaged and the neighbouring soft tissues was invaded in 1 case. On histological examination, the tumor was found to be composed of spindle cell with eosinophilic cytoplasm, some displayed interacting and some fascicle, the others irregular. Atypical tumor cells were not obvious and mitotic figures were rare. There were infiltrations of lymphocytes and plasma cells in tumor tissue. Immunohistochemical examination showed that the tumor cells were positive with Vimen-tin, Desmin, Actin and a - SMA. Electronic microscopy examination revealed that there were myofilaments with dense body and dense patch, a lot of rough endoplasmic reticula and procollagens in the cytoplasm of tumor cell. A lot of collagen fibers existed in the stroma. Conclusions IMTB is a rare kind of tumor of the bone with mild atypia. It should be distinguished from fibrosarco-ma, malignant fibrous histiocytoma, leiomyosarcoma and extra - abdominal dexmoide.