恶性腱鞘巨细胞瘤临床病理分析

Clinical pathologic analysis of malignant giant cell tumor of tendon sheath

目的探讨恶性腱鞘巨细胞瘤(malignant giant cell tumor of tendon sheath,MGCTS)的临床病理特征、免疫表型及鉴别诊断。方法对2例继发性MGCTS的石蜡切片分别做HE染色和免疫组化EnVision两步法染色,观察其临床病理及免疫表型特征,并与63例弥漫性腱鞘巨细胞瘤(diffuse-type giant cell tumor of tendon sheath,DGCTS)相比较,复习相关文献。结果MGCTS好发于中老年人,较良性GCTS发病年龄略大,通常见于下肢负重大关节周围。多为局部多次复发病例,影像学呈明显恶性改变,关节旁软组织有巨大肿块影,骨组织有广泛浸润性破坏,MRI显示各序列均见低信号结节,提示含铁血黄素沉积。2例MGCTS均继发于DGCTS,镜下仍保留部分DGCTS细胞构成,炎症背景中有较多大滑膜样单核细胞增生并伴有异型性,细胞胞质丰富,嗜伊红色,核偏位,排列松散,免疫标记示Clusterin强阳性。肿瘤细胞广泛浸润周围软组织及骨组织,并见大片凝固性坏死,较多脉管内瘤栓。MGCTS组织中Ki-67增殖指数略高于DGCTS。结论 MGCTS大多继发于DGCTS或色素性绒毛结节性滑膜炎,其真正的肿瘤细胞可能是恶变的大滑膜样单核细胞,此细胞Clusterin免疫组化标记阳性,有助于MGCTS的病理鉴别诊断。MRI显示各序列均见低信号结节,提示含铁血黄素沉积,是MGSTS影像学诊断的重要特征之一。MGCTS的诊断需综合评估诸多诊断依据,包括肿瘤细胞的异型性以及肿瘤体积大、广泛浸润性生长、大片坏死、脉管内瘤栓等生物学特征。

Purpose To investigate the clinicopathologic features,immunohistochemical features and differential diagnosis of malignant giant cell tumor of tendon sheath（MGCTS）.Methods Pathological examination and immunohistochemical study（EnVision method） were performed on 2 cases of MGCTS.The results were compared with sixty-three cases of diffused type（DGCTS） and literature was reviewed.Results MGCTS tumors tended to affect older patients than their diffuse-type counterpart.The lesions commonly occurred within the large weight-bearing joints.Recurrence was common and often multiple.Radiographic images of MGCTS tumors showed obviously malignant,ill-defined extra-articular soft tissue masses adjacent to the large joint and pathological fractures.MRI findings showed circumscribed nodular lesions with decreased signal intensity in both T1-and T2-weighted images,which indicating intratumoral hemorrhage of varying degrees.Both two cases of MGCTS showed metachronous sarcomatous histology several years after diagnosis of previously DGCTS.Histologically,MGCTS still remained the same cell components of DGCTS with proliferative large synovial-like mononuclear cells in inflammatory background.The large synovial-like mononuclear cells were rounded mononuclear cells with eosinophilic cytoplasm,slightly atypical,arranging loosely,and strong positive for clusterin.The tumor infiltrated into soft tissue and bone tissue with necrosis,and lots of intravascular tumor emboli could be indentified.The index of Ki-67 was a little higher than DGCTS.Conclusions MGCTS is an unusual synovial malignant tumor with concurrent or previous benign DGCTS/PVNS,poses challenges to diagnosis and prognostication.The true neoplastic cells may be the malignant transformation of large synovial-like mononuclear cells,stained for clusterin,which is an useful biological marker in pathological differential diagnosis.MRI findings show circumscribed nodular lesions with decreased signal intensity in both T1-and T2-weighted images,which indicating intratumoral hemorrhage of varying degrees,and maybe representing an important distinguishing feature.The pathological differential diagnosis of MGCTS should be based on many diagnosis features,including anaplastic cells,and large tumor size,large necrosis,more aggressive and destructive.