以肿瘤细胞中神经内分泌分化标记物的表达为特征的肿瘤被定义为神经内分泌肿瘤。本文报道了1例在食管胃交界处伴有少量乳头状腺癌成分的具有显著空泡核特征的神经内分泌癌(neuroendocrine carcinomas，NECs)。患者为男性，77岁，吞咽不畅1周。内镜检查提示食管胃结合部早期癌，活检诊断为低分化癌，遂行内镜黏膜下剥离术。组织学上，肿瘤呈现出由衬覆靴钉样细胞特征的典型分枝的乳头状结构(高分化)，到乳头的衬覆上皮增生形成筛孔状结构(中分化)，再到缺乏乳头结构的实性区(低分化)的连续性过程；在此过程中肿瘤细胞核内空泡呈现由轻微到明显，再到显著空泡特征的连续性变化。肿瘤主要由实性区构成(约占95%)，细胞单一，细胞体积大，核圆形或卵圆形至不规则形，核呈显著空泡状，空泡较大的核呈圆圈状，空泡内可见少许稀薄的弱嗜碱性或弱嗜酸细颗粒，空泡边缘不光滑。空泡外侧核染色质细颗粒状，核分裂多见(20~30个/mm²)，可见非典型核分裂，核仁易见，细胞质弱嗜酸性，细胞的界线不清楚。细胞排列呈巢状、梁索状或弥漫片状，部分排列呈腺管状。黏膜下层静脉内见癌栓；肿瘤内富含毛细血管的间质中伴有大量中性粒细胞浸润。免疫组织化学染色肿瘤实性区细胞突触素(synaptophysin，Syn)和嗜铬粒蛋白A(chromogranin A，CgA)阳性，而乳头状腺癌阴性。黏蛋白5AC(mucin 5AC，MUC5AC)乳头状腺癌弥漫阳性，而肿瘤实性区细胞阳性比例约为10%~15%。总之，该病例展示了NECs空泡状核特征的极端情况，极为罕见，从某种意义上说，扩展了NECs形态谱的边界; 了解这种核的极端空泡状特征有助于做出正确的病理诊断。

Neoplasms characterized by the expression of markers of neuroendocrine differentiation in neoplastic cells are defined as neuroendocrine neoplasms. A case of neuroendocrine carcinomas (NECs) with a small amount of papillary adenocarcinoma and significantly vacuolar nucleus at the esophagogastric junction was reported in this article. A 77-year-old male had dysphagia for one week. Endoscopy revealed early-stage esophagogastric junction carcinoma, and biopsy was diagnosed as poorly differentiated carcinoma. Endoscopic submucosal dissection was performed. Histologically, the papillary adenocarcinoma progresses from typically branching papillary structures (well-differentiated) to hyperplasia of the lining epithelium of the papilla to form a cribriform structure (moderately differentiated), to solid area lacking papillary structures (poorly differentiated). There was a continuous process, and during this process, the vacuoles in the nuclei of tumor cells showed progressive changes from mild to obvious and finally to significant vacuoles. The tumor was mainly composed of solid areas (about 95%), with single cell, large cell, round or oval to irregular nuclei, and significantly vacuolar nuclei, nuclei with larger vacuoles appeared in a loop, a few thin weakly basophilic or weakly eosinophilic fine particles could be seen in the vacuoles, and the vacuoles had rough edges. The nucleus chromatin at the outer edge of the vacuoles was fine particles, and mitosis was common (20-30/mm²), atypical mitosis could be seen, and nucleoli could be seen easily, the cytoplasm was weakly eosinophilic, and the boundaries of cells were unclear. The cells were arranged in a nested, trabecular, or diffuse sheet shape, with some arranged in a glandular tube shape. Tumor thrombus was found in the vein of submucosa; the interstitial tissue rich in capillaries within the tumor was accompanied by a large number of neutrophil infiltration. Immunohistochemical staining showed that the solid area of the tumor was positive for synaptophysin (Syn) and chromogranin A (CgA), while papillary adenocarcinoma was negative. Mucin 5AC (MUC5AC) was diffusely positive in papillary adenocarcinoma, while the proportion of positive cells in the solid area of the tumor was about 10% to 15%. In a word, this case showed the extreme situation of the vacuolar nuclear characteristics of NECs, extremely rare, in a sense, this case expanded the boundary of the morphological spectrum of NECs. Understanding the extreme vacuolar features of this nucleus is helpful to make a correct pathological diagnosis.

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作者贡献声明  侯卫华：资料收集、病理诊断和论文撰写；宋书杰、石中月和刘露：病例讨论和论文修改；金木兰：指导病理诊断，总体把关和审定论文; 所有作者均对最终文稿进行审读并确认。