胃淋巴上皮瘤样癌15例临床病理分析

Lymphoepithelioma-like carcinomas of the stomach: morphological, immunological and prognostic features

目的探讨胃淋巴上皮瘤样癌(LELC)的临床病理学特点。方法分析15例胃淋巴上皮瘤样癌的临床病理学特点,免疫组化法检测其免疫表型,比较其与相同分化程度和病理分期的非淋巴上皮瘤样胃腺癌的淋巴结转移率和预后。原位杂交法检测肿瘤组织中EB病毒的感染情况。结果 15例胃淋巴上皮瘤样癌均有显著的淋巴样间质,即大量淋巴细胞、浆细胞弥漫浸润,淋巴滤泡形成,癌细胞呈条索状、不规则的腺管或单个散在分布于大量淋巴细胞背景中。免疫组化:腺上皮细胞CK8/18、AE1/AE3和EMA(+),间质淋巴细胞CD20和CD3(+)。15例均无胃周围淋巴结转移,与同病理分期(T4a N0期)的非淋巴上皮瘤样胃低分化腺癌比较,差异显著(P<0.05)。3例肿瘤细胞EBER(+)。结论胃淋巴上皮瘤样癌是一种罕见类型的低分化腺癌,部分有EB病毒感染,具有特殊的临床病理学特点。

Objective Lymphoepithelioma-like carcinoma of the stomach is a rare adenocarcinoma accompanied by a large number of lymphocytes infiltration in the tumor and is easily misdiagnosed. It is necessary to investigate the clinicopathologic features of this unique tumor. Methods Fifteen cases of lymphoepithelioma-like carcinoma of the stomach in our hospital were collected for study. Results Histologically,fifteen cases were all accompanied by prominent lymphocytes infiltration. The lymphocytes extended into and throughout the wall of the stomach,with lymphoid follicle formation. The tumor cells were obscured by exuberant infiltration of lymphocytes. Immunohistochemistry results showed that the tumor cells were positive for CK8 /18 and AE1 / AE3 antibodies. The infiltrative lymphocytes included CD20-positive B lymphocytes and CD3-positive T lymphocytes. There was no lymph node metastasis in all the lymphoepithelioma-like carcinomas,and there was significant difference from the same stage（ T4a） of adenocarcinoma without majority of lymphocytes infiltration（ 0 /15 vs. 12 /15,P 〈 0.05）. Three cases were positive for Epstein-Barr encoded RNA-in situ hybridization（ EBER-ISH）. Conclusions Lymphoepithelioma-like carcinomas are rare subtype of adenocarcinoma with distinct clinicopathologic features and easily misdiagnosed as gastric mucosa associated lymphoid tissue（ MALT） lymphoma. IHC staining for cytokaretin is helpful for correct diagnosis. It is necessary to recognize the unique rare subtype of gastric adenocarcinoma.