Gastric intestinal metaplasia with basal gland atypia: a morphological and biologic evaluation in a large Chinese cohort.

Gastric intestinal metaplasia can display cytoarchitectural atypia that falls short of qualifying for dysplasia but can be classified as indefinite for dysplasia. Yet few studies have evaluated the prevalence, the morphologic, and biologic characteristics of this variant. Out of a cohort of 554 biopsies with chronic atrophic gastritis and/or dysplasia, we categorized the cases as either (1) simple intestinal metaplasia; (2) intestinal metaplasia with hyperplasia; (3) intestinal metaplasia with basal gland atypia; and (4) gastric dysplasia. The relationship between the subtypes and various clinicopathologic features, mucin immunophenotypes, and biologic characteristics was evaluated. The final cohort consisted of 424 cases of simple intestinal metaplasia, 93 intestinal metaplasia with hyperplasia, 16 intestinal metaplasia with basal gland atypia, and 21 gastric dysplasia. Intestinal metaplasia with basal gland atypia had a prevalence of 2.8% and similar to gastric dysplasia, 3.7%. Both of these lesions were similar in body/fundus distribution (12.5%) and paucity of goblet cells (68.8%). Intestinal metaplasia with basal gland atypia and gastric dysplasia seem to share some biologic similarities but with a lower frequency of alpha-methylacyl-CoA racemase expression (25% versus 62%), p53 expression (6.3% versus 47.6%), and increased Ki-67 index on surface/pit and isthmus in intestinal metaplasia with basal gland atypia. Alternatively, simple intestinal metaplasia and intestinal metaplasia with hyperplasia did not differ statistically with regard to the various characteristics evaluated. We concluded that gastric intestinal metaplasia can be divided into 2 broad categories that are readily defined by cytoarchitectural and biologic characteristics. Based on the characteristics of intestinal metaplasia with basal gland atypia and in keeping with others, we confirm that this subtype could represent a preneoplastic lesion that needs further evaluation.