原发性结肠透明细胞腺癌1例并文献复习

Clinicopathologic features of primary clear cell adenocarcinoma of the colon: report of a case and review of literature

目的探讨原发性结肠透明细胞腺癌(clear cell adenocarcinoma,CCA)的临床病理特征、免疫表型及鉴别诊断。方法对1例原发性结肠CCA临床特征、病理学形态和免疫表型进行分析,并复习相关文献。另选取5例经典结肠管状腺癌和5例肾透明细胞癌作为对照。结果患者男性,56岁,临床因黑便入院。全身检查未见结肠外其他器官占位性病变。结肠肿瘤是位于降结肠与乙状结肠交界处的隆起型肿物,肿物周围伴息肉样隆起,镜下见肿瘤由胞界清楚、胞质丰富的透明细胞组成,肿瘤细胞长柱状或多边形,胞质丰富,透明或空泡状,细胞核多位于基底部,胞核卵圆形或多角形、泡状,部分可见较明显的核仁。瘤细胞呈腺管状排列或相互融合呈筛状结构,部分瘤巢中央可见坏死。肿瘤侵及肠壁黏膜下层邻近肌层,未见脉管内癌栓,未见肠周淋巴结转移。免疫表型:CK20、CEA、CDX-2均呈阳性,CK7、CD10、RCCa、Pax-2、TTF-1均呈阴性。错配修复(mismatch repair,MMR)蛋白表达未见缺失(MLH1、MSH6、MSH2、PMS2均呈阳性)。病理诊断为原发性结肠CCA。结论原发性结肠CCA是一种非常少见的结肠癌,与普通结直肠腺癌及其他器官的透明细胞癌有某些形态上的重叠,免疫组化染色有助于诊断和鉴别诊断。

Purpose To observe and study the clinicopathological features, immunophenotype and differential diagnosis of primary clear cell adenocarcinoma （CCA） of the colon. Methods One case of primary CCA was investigated by clinical findings, histopathol- ogy and immunohistochemistry, and the related literature was reviewed. Additionally, 5 cases of classical colorectal carcinomas and 5 cases of clear cell renal cell carcinomas were selected as controls. Results The primary CCA in the junction of descending and sig- moid colon associated with adenoma in a 56-years-old man who presented at our hospital due to symptoms of melena. Histologic exami- nation revealed both CCA and moderately differentiated tubular adenocarcinoma. However, this tumor was mostly made up of CCA. In areas with CCA, the tumor was composed of both polygonal and columnar cells, and the cells had well-defined borders, with abundant clear and vesicular cytoplasm and more or less uniform round to oval nuclei with 1 N 2 nucleoli. The tumor was extended into but not beyond the submucosa. Vascular invasion and lymphatic involvement were not found. For immunohistochemical staining, the CCA showed positive staining for CK20, CEA, CDX-2, MLH1, MSH6, MSH2, and PMS2, but negative for CK7, CD10, RCCa, Pax-2, and TFF-1. Immunhistochemistry supported the diagnosis. Radiologic examinations showed no evidence of a tumor elsewhere in the body, including the kidneys or the gynecologic regions. A diagnosis of a CCA of the colon without regional lymph node metastasis was made. Conclusion The primary CCA of the colorectum is a rare colorectal carcinoma, which possesses overlapping histological fea- tures with clear cell carcinoma of other organs. Immunohistochemical staining is helpful for its diagnosis and differential diagnosis.