Confusion and prospects for carcinogenesis of gastric adenoma and dysplasia: What is the correct answer currently?

Table 1 The classifications of gastric adenoma of the Japanese Gastric Cancer Association and gastric superficial lesions of the WHO classification and the Vienna classification

Classification	Code	Diagnosis	Subtype	Subtype 2
JGCA[16]		Gastric adenoma	Intestinal type
			Gastric type	Pyloric gland type
				Foveolar type
WHO 2019[13]	8148/0	Glandular intraepithelial neoplasia, low grade
	8148/2	Glandular intraepithelial neoplasia, high grade
	8213/0	Serrated dysplasia, low grade
	8213/2	Serrated dysplasia, high grade	Intestinal-type dysplasia
			Foveolar-type (gastric type) dysplasia
			Gastric pit/crypt dysplasia
	8144/0	Intestinal-type adenoma, low grade
	8114/2	Intestinal-type adenoma, low grade	Sporadic intestinal-type gastric adenoma
			Syndromic intestinal-type gastric adenoma
	8210/0	Adenomatous polyp, low-grade dysplasia
	8210/2	Adenomatous polyp, high-grade dysplasia
Vienna[14]	3	Non-invasive low-grade neoplasia	Low-grade adenoma/dysplasia
	4	Non-invasive high-grade neoplasia
	4.1		High-grade adenoma/dysplasia
	4.2		Non-invasive carcinoma (carcinoma in situ)
	4.3		Suspicion of invasive carcinoma
	5	Invasive neoplasia
	5.1		Intramucosal carcinoma
	5.2		Submucosal carcinoma or beyond
Revised Vienna[15]	3	Mucosal low-grade neoplasia	Low-grade adenoma/dysplasia
	4	Mucosal high-grade neoplasia
	4.1		High-grade adenoma/dysplasia
	4.2		Non-invasive carcinoma (carcinoma in situ)
	4.3		Suspicious for invasive carcinoma
	4.4		Intramucosal carcinoma
	5	Submucosal invasion by carcinoma

JGCA: Japanese Gastric Cancer Association.