Iwaya Mai, Riddell Robert, Asano Koji, Kobayashi Kazuo, Uehara Takeshi, Ota Hiroyoshi
Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
Case Rep Gastroenterol. 2020 Aug 26;14(2):426-435. doi: 10.1159/000508413. eCollection 2020 May-Aug.
Alpha-fetoprotein (AFP)-producing gastric carcinomas (AFPGCs) are relatively rare tumors known to have a poor prognosis and commonly found as advanced lesions. Histologically, AFPGCs have been described as having hepatoid and fetal enteric (enteroblastic) morphology and are associated with conventional adenocarcinomas. Prior studies reported a hepatoid component present only in invasive areas and hypothesized that AFPGCs may develop hepatoid features during the process of tumor invasion. We report three cases of AFP-producing early gastric cancer which had an intramucosal hepatoid component. Immunohistochemistry showed that the hepatoid component was diffusely immunoreactive for SALL4, AFP, arginase-1, and HepPar1, and focally for CDX2 and PDX1. An intramucosal transition between the hepatoid component and conventional intramucosal adenocarcinoma was identified. Two patients also had a coexistent fetal enteric component, which was admixed with a hepatoid component. Although at an early stage one patient subsequently developed liver metastasis and a second patient was suspected of having liver metastasis, these were not biopsy-proven. The latter patient had a previous history of hepatocellular carcinoma (HCC) and SALL4 was used on the HCC to distinguish metastatic/further HCC from a gastric metastatic primary with hepatoid differentiation.
产生甲胎蛋白（AFP）的胃癌（AFPGC）是相对罕见的肿瘤，已知预后较差，且通常以进展期病变形式出现。从组织学上看，AFPGC被描述为具有肝样和胎儿肠道（成肠细胞）形态，并且与传统腺癌相关。先前的研究报告称肝样成分仅存在于浸润区域，并推测AFPGC可能在肿瘤浸润过程中形成肝样特征。我们报告了3例产生AFP的早期胃癌病例，其黏膜内存在肝样成分。免疫组织化学显示，肝样成分对SALL4、AFP、精氨酸酶-1和HepPar1呈弥漫性免疫反应，对CDX2和PDX1呈局灶性免疫反应。在肝样成分和传统黏膜内腺癌之间发现了黏膜内转变。2例患者还同时存在胎儿肠道成分，与肝样成分混合存在。尽管1例患者随后在早期发生了肝转移，另1例患者疑似发生肝转移，但均未经活检证实。后1例患者既往有肝细胞癌（HCC）病史，对HCC使用SALL4来区分转移性/进一步的HCC与具有肝样分化的胃转移性原发肿瘤。
