Watanabe S, Torii H, Matsuyama T, Harada S
Department of Dermatology, Teikyo University School of Medicine, Tokyo, Japan.
Am J Dermatopathol. 1996 Jun;18(3):308-13. doi: 10.1097/00000372-199606000-00012.
A 47-year-old woman noticed a nodule on her right shoulder that had been gradually increasing in size without symptoms. Histologic features of the biopsied nodule included round to irregularly shaped epithelial lobules demarcated by abundant sclerotic stroma located within the lower dermis and extending to the subcutis. The epithelial lobules consisted of cuboidal to columnar basaloid cells and were frequently arranged in narrow strands with many bifurcations and branching. Cystic structures containing lamellar keratinous material were occasionally found in connection with the lobules. The histologic findings were interpreted as trichoblastic fibroma. Immunohistochemical studies with antibodies directed against cytokeratins (CK) and involucrin revealed positive staining in most of the tumor cells with RCK102 and 34 beta E12 antikeratin antibodies, whereas the epithelial cords and the peripheral cells of the cystic structures stained with 170.2.14, 4.1.18, and CAM 5.2 antikeratin antibodies. However, CK1 or simple epithelial cytokeratins were not detected in any neoplastic elements. Based on comparative immunohistochemical findings in normal hair follicles, we propose that trichoblastic fibroma may first differentiate toward the outermost cell layer of the outer root sheath between the lower permanent portion and the upper transient portion and then into various other parts of the hair follicle.
一名47岁女性注意到其右肩部有一个结节，该结节大小逐渐增大且无症状。活检结节的组织学特征包括圆形至不规则形的上皮小叶，由位于真皮下部并延伸至皮下组织的大量硬化性间质分隔。上皮小叶由立方状至柱状的基底样细胞组成，常排列成具有许多分叉和分支的细条索状。偶尔可见与小叶相关的含有板层状角蛋白物质的囊性结构。组织学表现被解释为毛发母细胞性纤维瘤。用针对细胞角蛋白（CK）和外皮蛋白的抗体进行免疫组织化学研究显示，大多数肿瘤细胞用RCK102和34βE12抗角蛋白抗体呈阳性染色，而囊性结构的上皮索和周边细胞用170.2.14、4.1.18和CAM 5.2抗角蛋白抗体染色。然而，在任何肿瘤成分中均未检测到CK1或简单上皮细胞角蛋白。基于正常毛囊的比较免疫组织化学结果，我们提出毛发母细胞性纤维瘤可能首先向下部永久部分和上部过渡部分之间的外根鞘最外层细胞层分化，然后再向毛囊的其他各个部分分化。
