title: Hepatoid adenocarcinoma of the stomach is a special and easily misdiagnosed or missed diagnosed subtype of gastric cancer with poor prognosis but curative for patients of pN0/1: the experience of a single center.
abstract: OBJECTIVE
  To document the clinicopathological characteristics and analyze the possible reasons for misdiagnosis or missed diagnosis of hepatoid adenocarcinoma of the stomach (HAS), using data from a single center.
  
  
  METHODS
  We retrospectively analyzed 19 patients initially diagnosed as HAS and 7 patients initially diagnosed as common gastric cancer with high levels of serum α-fetoprotein (AFP). All had undergone surgical treatment, except 3 patients only had biopsies at our hospital. Immunohistochemistry for AFP and Hepatocyte antigen was performed. Final diagnosis for these 26 patients were made after HE and immunohistochemistry slides reviewed by 2 experienced pathologists. Prognostic factors were determined by univariate analysis.
  
  
  RESULTS
  Nineteen cases were confirmed to be HAS. A total of 4 out of 19 cases initially diagnosed as HAS and 4 out of 7 cases initially diagnosed as common gastric adenocarcinoma were misdiagnosed/missed diagnosed, thus, the misdiagnosis/missed diagnosis rate was 30.8% (8/26). The incidence of HAS among gastric cancer in our center was 0.19% (19/9915). Sixteen (84.2%) patients showed T stages greater than T2, 12 (70.6%) patients had positive lymph nodes in 17 available patients and 3 (15.8%) of the patients with tumors presented liver metastasis at the time of diagnosis. Histologically, cytoplasmic staining types included 10 cases of eosinophilic, 1 case of clear, 5 cases of clear mixed with eosinophilic and 3 cases of basophilic. Fourteen (73.7%) patients expressed AFP, whereas only 6 (31.6%) were hepatocyte-positive. Univariate analysis showed that N stage (HR 2.429, P=0.007) and tumor AFP expression (HR 0.428, P=0.036) were significantly associated with disease-free survival. The median overall survival time was 12.0 months, and the median disease-free survival time was 7.0 months. Four (80%) of 5 N0 patients and 2 (50%) of 4 N1 patients survived without progression, but no N2-3 patients survived.
  
  
  CONCLUSIONS
  HAS remains easily being misdiagnosed/missed diagnosed based on a pathological examination, probably because the condition is rare and has various cytoplasmic types. Although the survival rate for HAS is poor, a curative effect may be achieved for N0 or N1 cases.
authors.affiliation: Department of Abdominal Surgical Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of General Surgery, Beijing Puren Hospital Beijing 100062, China.
authors.forename: Zhonghai
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Abdominal Surgical Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Abdominal Surgical Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Abdominal Surgical Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Chunguang
authors.initials: C
authors.lastname: Guo
authors.affiliation: Department of Pathology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Diagnostic Radiology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.affiliation: Department of Abdominal Surgical Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Pathology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.affiliation: Department of Pathology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Xue
authors.affiliation: Department of Abdominal Surgical Oncology, Cancer Hospital and Institute, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021, China.
authors.forename: Dongbing
authors.initials: D
authors.lastname: Zhao
keywords: Stomach; diagnosis; hepatoid adenocarcinoma; survival; α-fetoprotein (AFP)