Prieto V G, Reed J A, Shea C R
Department of Pathology, New York Hospital-Cornell Medical Center, New York, USA.
J Cutan Pathol. 1995 Aug;22(4):336-41. doi: 10.1111/j.1600-0560.1995.tb01416.x.
Dermatofibromas (DF) are common, benign skin tumors composed predominantly of cells having elongated nuclei and very scant cytoplasm (i.e., fibroblasts) and capillaries in a collagenous stroma. Some authors distinguish DF from benign fibrous histiocytomas (BFH), which are composed of cells with round to oval nuclei and abundant cytoplasm (i.e., histiocytes). In general, this group of tumors expresses factor XIIIa but not the antigen recognized by MAC 387. However, immunohistochemical differences specifically between DF and BFH have not been reported. We have studied the immunophenotype of 23 lesions having morphologic features predominantly either of DF (17 cases) or BFH (6 cases) using antibodies against desmin (muscle marker), alpha-smooth-muscle actin (muscle and myofibroblast marker), CD68 and HAM56 antigen (markers commonly expressed by macrophages, so called "histiocytic" markers), CD34 (a marker present in hematopoietic, vascular, and occasional dermal dendritic cells), and factor XIIIa (a transglutaminase present in many cells including dermal dendrocytes). Many spindle-shaped cells expressed alpha-smooth-muscle actin while many large, round cells expressed the histiocytic markers. However, most lesions expressed at least focally both alpha-smooth-muscle actin and "histiocytic" markers. Thus a clear-cut distinction between DF and BFH could not be made based on immunophenotype alone. Additionally, the prominent alpha-smooth-muscle actin immunoreactivity and desmin non-reactivity suggests myofibroblastic differentiation in the spindle-cell regions of these tumors, and indicates that expression of alpha-smooth-muscle actin cannot be used as definitive proof of muscle differentiation in spindle-cell tumors. We conclude that DF and BFH are not discrete entities, but represent polar expressions of one nosologic entity exhibiting both myofibroblastic and "histiocytic" differentiation.
皮肤纤维瘤（DF）是常见的良性皮肤肿瘤，主要由细胞核呈细长形且细胞质极少的细胞（即成纤维细胞）和胶原基质中的毛细血管组成。一些作者将DF与良性纤维组织细胞瘤（BFH）区分开来，后者由细胞核呈圆形至椭圆形且细胞质丰富的细胞（即组织细胞）组成。一般来说，这组肿瘤表达因子ⅩⅢa，但不表达MAC 387识别的抗原。然而，关于DF和BFH之间具体的免疫组化差异尚未见报道。我们使用抗结蛋白（肌肉标志物）、α - 平滑肌肌动蛋白（肌肉和肌成纤维细胞标志物）、CD68和HAM56抗原（巨噬细胞通常表达的标志物，即所谓的“组织细胞”标志物）、CD34（存在于造血细胞、血管细胞和偶尔的真皮树突状细胞中的标志物）以及因子ⅩⅢa（存在于包括真皮树突状细胞在内的许多细胞中的转谷氨酰胺酶）的抗体，研究了23例主要具有DF形态特征（17例）或BFH形态特征（6例）的病变的免疫表型。许多梭形细胞表达α - 平滑肌肌动蛋白，而许多大的圆形细胞表达组织细胞标志物。然而，大多数病变至少局灶性地同时表达α - 平滑肌肌动蛋白和“组织细胞”标志物。因此，仅基于免疫表型无法明确区分DF和BFH。此外，显著的α - 平滑肌肌动蛋白免疫反应性和结蛋白无反应性提示这些肿瘤的梭形细胞区域存在肌成纤维细胞分化，表明α - 平滑肌肌动蛋白的表达不能作为梭形细胞肿瘤中肌肉分化的确切证据。我们得出结论，DF和BFH并非截然不同的实体，而是代表了一个疾病实体的两极表达，该实体同时表现出肌成纤维细胞和“组织细胞”分化。
