Extra-ampullary duodenal adenocarcinomas are rare, and when studied, frequently have been grouped with jejunoileal adenocarcinomas. Nevertheless, anecdotal experiences suggest that these neoplasms may present 2 or more distinct phenotypes. To better characterize these neoplasms, we performed a retrospective review of 38 cases with a special focus on the morphologic and immunophenotypic characteristics and their clinicopathologic significance. Our cohort of extra-ampullary duodenal adenocarcinomas was classified on the basis of the morphologic features into gastric type (n=19, 50%), intestinal type (n=14, 37%), pancreaticobiliary type (n=2, 5%), and others (n=3, 8%). Most gastric-type adenocarcinomas (n=18, 95%) developed in the proximal duodenum, whereas the other types were located equally in the proximal and distal duodenum. Intestinal-type dysplasia was present at the periphery of 8 (57%) intestinal-type adenocarcinomas, and 8 (42%) gastric-type adenocarcinoma were associated with gastric-type dysplasia. Gastric foveolar metaplasia (n=12) and Brunner gland hyperplasia (n=10) were exclusively recognized adjacent to gastric-type adenocarcinomas. Notably, intestinal-type histology and the absence of lymph node metastasis were significantly associated with favorable disease-free survival in univariate and multivariate analyses. In summary, this study demonstrated that 2 major subsets of extra-ampullary duodenal adenocarcinoma, intestinal type and gastric type, are associated with distinct histopathologic features and clinical behavior.
壶腹外十二指肠腺癌罕见，并经常把它们归于空肠回肠腺癌一起研究。然而，口口相传的经验表明这些肿瘤可呈现2种或更多不同的表型。为了更好了解这些肿瘤的特征，我们回顾性研究了38例壶腹外十二指肠腺癌，重点关注其形态学和免疫表型特征及它们的临床病理学意义。我们的壶腹外十二指肠腺癌病例以形态学特征为基础分为胃型（n=19, 50%），肠型（n=14, 37%），胰胆管型（n=2, 5%）和其他型（n=3, 8%）。大多数胃型腺癌（n=18, 95%）发生于十二指肠近端，而其他型平均分布于十二指肠近端和远端。8例（57%）肠型腺癌的周围可见肠型异型增生，8例（42%）胃型腺癌与胃型异型增生有关。胃小凹化生（n=12）和Brunner腺增生（n=10）仅出现于邻近胃型腺癌的区域。值得注意的是，单因素和多因素分析表明组织学为肠型和无淋巴结转移与无病生存显著相关。总之，本研究表明壶腹外十二指肠腺癌的2个主要亚型，肠型和胃型，有不同的组织病理学特征和临床行为。