黏液炎性纤维母细胞肉瘤

Myxoinflammatory fibroblastic sarcoma

患者男，73岁。左小腿红斑、斑块伴微痒2年，加重为结节、肿块伴疼痛半年余。皮肤科检查：左小腿伸侧、腓侧中下1／3处多个大小不一红斑、斑块、结节、肿块。肿块质地坚韧，基底深在，可活动，边界不清，压痛明显。肿块表面皮肤部分外观正常。组织病理学检查：表皮未见明显异常；真皮中下部及皮下脂肪层可见梭形细胞及大小不一、胞体大、胞质红染、核大、浓染不规则的细胞，呈片状分布，其中可见病理性核分裂象，间质内可见淡蓝染物质，其间杂有淋巴细胞浸润。间质阿新蓝染色阳性。免疫组化染色：梭形细胞及异形大细胞弥漫性强阳性表达波形蛋白（Vim），30％～40％瘤细胞表达Ki67，CD34和CD68部分细胞阳性，而白细胞共同抗原、人黑素瘤S100蛋白、pCK、CD31、平滑肌肌动蛋白及结蛋白均为阴性。诊断：黏液炎性纤维母细胞肉瘤。

A 73-year-old male presented with mildly pruritic erythematous papules and plaques on the left leg for two years, which had developed into painful nodules and masses for half a year. Dermatological examination revealed multiple irregularly sized erythematous patches, plaques, nodules and masses on the distal one third of the extensor and fibular aspects of the left leg. The masses were hard, deeply infiltrating into the subcutaneous layer and ill-defined with tenderness and limited mobility. The skin covering the masses was partly normal. Histopathologically, there were focal aggregates of spindle cells and large cells of uneven size with red-stained cytoplasm and irregularly-shaped, heavily-stained huge nuclei in the mid and deep dermis as well as subcutaneous fat layer, with no obvious abnormality in the epidermis. Atypical mitoses were seen. There were light blue-stained substances admixed with lymphocytes in the Alcian blue-stained stroma. Immunohistochemistry revealed that the spindle cells and atypical large cells diffusely expressed vimentin. Of the tumor ceils, 30% - 40% stained positive for Ki67, some for CD34 and CD68, while all stained negative for leukocyte common antigen, S100, pan cytokeratin, CD31, smooth muscle actin and desmin. A diagnosis of myxoinflammatory fibroblastic sarcoma was made.