%0 Journal Article
%T Gastric Composite Tumor of Alpha Fetoprotein-Producing Carcinoma/Hepatoid Adenocarcinoma and Endocrine Carcinoma with Reference to Cellular Phenotypes
%A Akira Suzuki
%A Naohiko Koide
%A Masato Kitazawa
%A Akiyoshi Mochizuka
%A Hiroyoshi Ota
%A Shinichi Miyagawa
%J Pathology Research International
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/201375
%X Alpha-fetoprotein-producing carcinoma (AFPC)/hepatoid adenocarcinoma (HAC) and neuroendocrine carcinoma (NEC) are uncommon in the stomach. Composite tumors consisting of these carcinomas and their histologic phenotypes are not well known. Between 2002 and 2007, to estimate the prevalence of composite tumors consisting of tubular adenocarcinoma, AFPC/HAC and NEC, we reviewed specimens obtained from 294 consecutive patients treated surgically for gastric cancer. We examined histological phenotype of tumors of AFPC or NEC containing the composite tumor by evaluating immunohistochemical expressions of MUC2, MUC5AC, MUC6, CDX2, and SOX2. Immunohistochemically, AFPC/HAC dominantly showed the intestinal or mixed phenotype, and NEC frequently showed the gastric phenotype. In the composite tumor, the tubular and hepatoid components showed the gastric phenotype, and the neuroendocrine component showed the mixed type. The unique composite tumor predominantly showed the gastric phenotype, and the hepatoid and neuroendocrine components were considered to be differentiated from the tubular component. 1. Introduction Alpha-fetoprotein (AFP) is a fetal protein produced by yolk sac cells, fetal hepatic cells, and some fetal gastrointestinal cells [1]. AFP-producing carcinoma (AFPC) is rare in the stomach [2], although gastric adenocarcinoma is one of the most common manifestations of AFPC [3]. Ishikura et al. [4] reported that hepatoid adenocarcinoma (HAC) is characterized by both hepatoid differentiation and AFP production, while the histological features of hepatoid differentiation in gastric AFPC have been determined. Gastric AFPC or HAC frequently displays aggressive behavior [2, 5]; however, these tumors exhibit many unresolved clinical and histopathological features. On the other hand, neuroendocrine carcinoma (NEC), including small cell carcinoma, is rare in the stomach [6], and its clinicopathological features and clinical outcome have been characterized recently [7, 8]. Both AFPC and NEC were classified as special types of gastric carcinomas by the Japanese Classification of Gastric Carcinoma [9]. Composite gastric tumors, consisting of special types of carcinoma, have been insufficiently investigated. A composite gastric tumor usually consists of both a common and a special type of carcinoma, that is, well- or moderately differentiated adenocarcinoma and HAC [4]. Gastric adenocarcinomas have been histopathologically classified into four categories based on their cellular phenotype [10]. Several cellular markers, including MUC2, MUC5AC, and MUC6, have been used
%U http://www.hindawi.com/journals/pri/2012/201375/