Laskin William B, Miettinen Markku
Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Ill, USA.
Arch Pathol Lab Med. 2003 Sep;127(9):1161-8. doi: 10.5858/2003-127-1161-ESNIBO.
Epithelioid sarcoma has a distinctive epithelioid phenotype and characteristically exhibits immunohistochemical reactivity for epithelial markers (keratins and epithelial membrane antigen) and mesenchymal markers (most notably vimentin and CD34). Antibodies to certain keratin subunits and other novel antigens now available to surgical pathologists have not been tested on a large number of cases.
To assist in the differential diagnosis of epithelioid sarcoma and to help elucidate its histogenesis through an expanded immunohistochemical profile.
Immunohistochemical testing with diverse antibodies was performed on 95 archived epithelioid sarcomas including 73 classic and 22 histologically variant subtypes retrieved from the files of the Armed Forces Institute of Pathology.
Immunohistochemical reactivity (number positive/number of cases tested [percent positive], frequency of staining) included keratin 14 (31/64 [48%], variable), gamma-catenin (35/74 [47%], variable), keratin 5/6 (10/33 [30%], focal), calretinin (8/40 [20%], focal), keratin 20 (11/71 [15%], focal), p63 (3/20 [15%], focal), whereas 9 invasive cutaneous squamous cell carcinomas showed strong p63 positivity, epithelial-specific antigen (10/74 [14%], variable), CD117/Kit (5/37 [14%], focal), keratin 15 (3/23 [13%], rare cell), mesothelin (2/64 [3%], rare cell), and CD10 (1/41 [2%], rare cell). No reactivity was observed for keratins 2, 5, and 10.
Diagnostically, p63 and keratin 5/6 distinguish cutaneous squamous cell carcinoma (positive) from epithelioid sarcoma (usually negative). No single immunomarker was able to distinguish the main 4 histologic subtypes of epithelioid sarcoma, indicating that they are all histogenetically related lesions. The limited expression of specific keratin subtypes used in our study supports the notion that epithelioid sarcoma is a mesenchymal neoplasm capable of partial epithelial transformation.
上皮样肉瘤具有独特的上皮样表型，其特征是对上皮标志物（角蛋白和上皮膜抗原）和间充质标志物（最显著的是波形蛋白和CD34）表现出免疫组化反应性。目前手术病理学家可用的针对某些角蛋白亚基和其他新抗原的抗体尚未在大量病例中进行测试。
通过扩展免疫组化谱辅助上皮样肉瘤的鉴别诊断并帮助阐明其组织发生。
对95例存档的上皮样肉瘤进行了多种抗体的免疫组化检测，这些病例包括从武装部队病理研究所档案中检索到的73例经典型和22例组织学变异型亚型。
免疫组化反应性（阳性例数/检测病例数[阳性百分比]，染色频率）包括角蛋白14（31/64[48%]，可变）、γ连环蛋白（35/74[47%]，可变）、角蛋白5/6（10/33[30%]，局灶性）、钙视网膜蛋白（8/40[20%]，局灶性）、角蛋白20（11/71[15%]，局灶性）、p63（3/20[15%]，局灶性），而9例浸润性皮肤鳞状细胞癌显示p63强阳性，上皮特异性抗原（10/74[14%]，可变）、CD117/Kit（5/37[14%]，局灶性）、角蛋白15（3/23[13%]，罕见细胞）、间皮素（2/64[3%]，罕见细胞）和CD10（1/41[2%]，罕见细胞）。未观察到角蛋白2、5和10的反应性。
在诊断方面，p63和角蛋白5/6可将皮肤鳞状细胞癌（阳性）与上皮样肉瘤（通常阴性）区分开来。没有单一的免疫标志物能够区分上皮样肉瘤的4种主要组织学亚型，这表明它们都是组织发生相关的病变。我们研究中使用的特定角蛋白亚型的有限表达支持上皮样肉瘤是一种能够发生部分上皮转化的间充质肿瘤这一观点。
