48例软组织平滑肌肉瘤的病理及免疫组化研究

Leiomyosarcoma:a pathological and immunohistochemical study of 48 soft tissue cases

目的 :研究软组织平滑肌肉瘤 (LMS)组织学亚型的病理形态特点及其对各种肌源性标记的表达。方法 :对 48例软组织LMS作了形态学观察、组织学分型和免疫组化研究。结果 :其组织学亚型依次为普通型 (C LMS) (77 1% ) ,多形性 (P LMS)(12 5 % ) ,上皮样 (E LMS) (6 3% )和伴有破骨细胞样巨细胞 (OGC LMS) (4 2 % ) ;后三种亚型和某些低分化C LMS易误诊为恶性纤维组织细胞瘤 (MFH) ;Des、MSA和α SMA阳性率分别为 2 8 9%、6 8 1%和 10 0 % ,Des和MSA阳性表达与组织学分级呈负相关。结论 :对低分化和特殊亚型LMS的形态特点应提高认识。多形性肉瘤的诊断除注意其组织结构外 ,还应特别注意瘤细胞的形态特征 ;α SMA是LMS较特异和最敏感的标记。

Purpose To study the pathological features of various subtypes of the primary leiomyosarcoma(LMS) of soft tissue and its expressions of different kinds of myogenic markers. Methods Forty eight cases of LMS in soft tissue were investigated by morphological observations, histological classifications and immunohistochemical study. Results Conventional leiomyosarcoma was by far the most common subtype (77 1%), the other subtypes were pleomorphic leiomyosarcoma(12 5%), epithelioid leiomyosarcoma(6 3%) and leiomyosarcoma with osteoclast like giant cells(4 2%), the latter three subtypes and some poorly differentiated C LMSs were easily misdiagnosed as malignant fibrous histocytoma. IHC staining showed that the percentage of Des, MSA and α SMA positive expression in LMS were 28 9%, 68 1% and 100%, respectively. There were negative relationships between histological grading and the positive expression of Des and MSA. Conclusion It is important to know the morphology of poorly differentiated C LMS and some subtypes of LMS. The diagnosis of pleomorphic sarcoma should be careful. The tumor cell morphology as well as its histological structure play the same important role in the diagnosis. α SMA is the most sensitive and more specific marker for leiomyosarcoma.