Department of Pathology, The University of Texas, MD, Anderson Cancer Center, Houston, TX 77030, USA.
Mod Pathol. 2013 Mar;26(3):370-84. doi: 10.1038/modpathol.2012.172. Epub 2012 Oct 5.
Signet-ring cell mesothelioma is uncommon and only two case reports have been published on this mesothelioma variant, both of which were initially misdiagnosed as signet-ring cell carcinoma. Herein are reported 23 signet-ring cell mesotheliomas that were investigated by immunohistochemistry, 12 of which were also studied by electron microscopy. Twenty-one of the cases originated in the pleura and two in the peritoneum. For comparison purposes and in order to determine the value of these techniques in the differential diagnosis of these tumors, seven cases of signet-ring cell lung adenocarcinoma were also studied. All signet-ring cell mesotheliomas were positive for calretinin, keratin 5/6, keratin 7, and mesothelin, 93% for podoplanin, and 91% for WT1; whereas, none reacted for MOC-31, CEA, TAG-72, CD15, TTF-1, napsin A, or CDX2. Among signet-ring cell lung adenocarcinomas, 100% were positive for keratin 7, CEA, and napsin A, 86% each for TTF-1 and TAG-72, 71% for CD15, and 14% for mesothelin, while all were negative for calretinin, keratin 5/6, WT1, podoplanin, and CDX2. After analyzing the results, it is concluded that the panels of markers used in the differential diagnosis of this mesothelioma variant should include those markers that are usually expressed in mesotheliomas (eg, calretinin, keratin 5/6, WT1, and podoplanin), broad-spectrum carcinoma markers that are frequently expressed in adenocarcinomas regardless of their site of origin (eg, MOC-31 and CEA), and organ-associated markers (eg, TTF-1 and napsin A for lung), which allow the site of origin of a metastatic adenocarcinoma to be established. Electron microscopy can be very useful as it permits the identification of characteristic ultrastructural mesothelioma and adenocarcinoma markers, and it also allows a better understanding of the morphologic features seen on routine light microscopy. Pathologists should be aware of this mesothelioma subtype as it can potentially be confused with other tumors that exhibit signet-ring features.
印戒细胞型间皮瘤较为罕见，仅有两份关于该变异型间皮瘤的病例报告发表，这两份报告最初均误诊为印戒细胞癌。本文报告了 23 例经免疫组织化学检查的印戒细胞型间皮瘤，其中 12 例还进行了电镜检查。21 例病例起源于胸膜，2 例起源于腹膜。为了进行对比并确定这些技术在这些肿瘤的鉴别诊断中的价值，我们还研究了 7 例印戒细胞肺腺癌。所有印戒细胞型间皮瘤均表达 calretinin、角蛋白 5/6、角蛋白 7 和间皮素，93%表达 podoplanin，91%表达 WT1；而无一例表达 MOC-31、CEA、TAG-72、CD15、TTF-1、 napsin A 或 CDX2。在印戒细胞肺腺癌中，100%表达角蛋白 7、CEA 和 napsin A，86%表达 TTF-1 和 TAG-72，71%表达 CD15，14%表达间皮素，而无一例表达 calretinin、角蛋白 5/6、WT1、podoplanin 和 CDX2。分析结果后得出结论，用于该间皮瘤变异型鉴别诊断的标志物组合应包括通常在间皮瘤中表达的标志物（例如 calretinin、角蛋白 5/6、WT1 和 podoplanin）、广泛表达于腺癌的广谱癌标志物（例如 MOC-31 和 CEA），以及器官相关标志物（例如用于肺的 TTF-1 和 napsin A），这些标志物可确定转移性腺癌的起源部位。电镜检查非常有用，因为它可以识别特征性的超微结构间皮瘤和腺癌标志物，并且还可以更好地理解常规光镜下所见的形态学特征。病理学家应该了解这种间皮瘤亚型，因为它可能与表现出印戒特征的其他肿瘤混淆。
