黏液炎性纤维母细胞性肉瘤的临床病理学观察

Myxoinflammatory fibroblastic sarcoma： a clinicopathologic study of 6 cases with review of literature

目的 探讨黏液炎性纤维母细胞性肉瘤（MIFS）的临床病理学特征、诊断和鉴别诊断.方法 对6例MIFS的临床资料、光镜形态和免疫表型进行回顾性分析,并复习文献.结果 6例均发生于成年人,其中男性2例,女性4例,中位和平均年龄分别为47岁和50岁.肿瘤位于下肢3例,上肢2例,腋窝1例.临床上,患者多表现为肢体局部肿胀或缓慢性生长的肿块,伴有轻微疼痛或胀痛感.大体上,肿瘤呈灰白色结节状,直径2.5～4.6 cm（平均3.4 cm）.镜下,肿瘤由黏液样区域、玻璃样变区域和炎性区域混杂组成.除梭形细胞外,在3种区域内均可见到呈单个散在分布或小簇状分布的异型大细胞,核大、核仁明显,形态上类似病毒细胞、R-S细胞或神经节细胞,核分裂象罕见.在黏液样区域内还可见到黏液湖形成及漂浮的单泡状或多泡状脂母样细胞.免疫组织化学标记显示,畸形大细胞主要表达波形蛋白,其他标记包括白细胞共同抗原、CD30、CD68、CD34、S-100蛋白、HMB45、细胞角蛋白和肌动蛋白等均为阴性.随访4例,2例于局部切除后复发.结论 MIFS是一种低度恶性的纤维母细胞性肉瘤,易被误诊为良性病变,熟悉其临床病理学特点有助于诊断和鉴别诊断.

Objective To study the clinicopathologic features, immunophenotypes and differential diagnosis of myxoinflammatory fibroblastic sarcoma （MIFS）. Methods The clinical and pathologic features of 6 cases of MIFS were analyzed. lmmunohistochemical study was performed using the standard EnVision method. Results There were altogether 2 adult males and 4 adult females （ median age =47 years and mean age = 50 years）. Three cases were located in the lower extremities, 2 in the upper limbs and 1 in the axillary region. Common presentation included slowly growing mass or swelling in the extremities, accompanied by mild pain or tenderness. Grossly, the tumor appeared multinodular and ranged from 2. 5 cm to 4. 6 cm in diameter （ mean = 3.4 cm）. Microscopically, there was a dense inflannatory infiltrate merging with hyaline and myxoid zones in various proportions. Spindle-shaped tumor cells were seen admixed with large atypical cells which distributed singly or in small clusters, amongst an inflammatory, hyaline or a myxoid background. These atypical cells had large nuclei and prominent nucleoli, resembling virocytes, Reed-Sternberg cells or ganglion cells. Mitotic figures were rarely identified. Extracellular mucin associated with scattered monovacuolated or multivacuolated lipeblast-like cells was noted. Immunohistochemically, these bizarre cells were consistently positive for vimentin, but negative for a panel of antibodies including LCA,CD15, CD30, CD34, CD68, S-100, HMB45, AE1/AE3, smooth muscle actin and desmin. Follow-upresult was available in 4 cases; and 2 of them showed local recurrence after an incomplete excision. There was no evidence of distant metastasis. Conclusions MISF is a low-grade sarcoma of fibroblastic differentiation. Awareness of the clinical and pathologic characteristics is helpful in arriving at the correct diagnosis and distinction from benign inflammatory fibromyxoid lesions.