Gastric adenocarcinoma of fundic gland type: report of three cases.

Recently, fundic gland type gastric adenocarcinoma (GA-FG) has been reported as a new entity. This report describes GA-FG among Koreans for the first time. From March 2008 to July 2010 we identified only three cases of GA-FG out of over 6,000 GAs resected by endoscopy or surgery. Cell differentiation by mucin proteins, pepsinogen-I, and H+/K+-ATPase was evaluated. All three cases were male patients and diagnosed as early stage GA. Histologically, GA-FGs were well-differentiated adenocarcinoma with pale gray-blue, basophilic columnar or cuboidal cells and mildly enlarged nuclei, resembling chief cells. All three cases were positive for pepsinogen-I and were classified as gastric mucin phenotype. Among three histologic subtypes of GA-FG, since tumors were mainly composed of chief cells, our three cases were classified as chief cell predominant type. In conclusion, GA-FG is very rare among Koreans and pepsinogen-I and MUC6 expression are typical immunohistochemical findings in GA-FG suggesting differentiation toward fundic glands.