| Theme |
Reconsideration of Gastritis |
| Title |
Gastric Adenocarcinoma of Fundic Gland Type |
| Author |
Hiroya Ueyama |
Department of Gastroenterology, Juntendo University, School of Medicine |
| Author |
Takashi Yao |
Department of Human Pathology, Juntendo University, School of Medicine |
| Author |
Akihito Nagahara |
Department of Gastroenterology, Juntendo University, School of Medicine |
| [ Summary ] |
Gastric adenocarcinoma of fundic gland type (GAFG) is recently proposed as new and rare variant of gastric adenocarcinoma per the World Health Organization Classification of Tumors, 5th Edition. Histopathologically, GAFG is classified into oxyntic‒gland adenoma and gastric adenocarcinoma of fundic gland type, based on the depth of tumor invasion. GAFG presents with distinct clinicopathological, immunohistochemical, and endoscopic features. With regard to biological behavior, GAFG is considered less aggressive because it shows low cellular atypia, no lymphovascular invasion, low proliferative activity, lack of p53 protein overexpression, and good prognosis. Recent reports have described several cases of an aggressive variant of GAFG with high cellular atypia. One of the variants showed differentiation toward gastric foveolar epithelium in addition to fundic gland differentiation, and this category of tumors was defined as gastric adenocarcinoma of fundic gland mucosal type (GAFGM). GAFGM may be the appropriate nomenclature for an aggressive variant of GAFG with foveolar differentiation. Further studies are warranted to gain a deeper understanding of the natural history and clinicopathological features of GAFG (including GAFGM), by assessing long‒term outcomes and the new classification based on the grade of atypia and cell differentiation. |