The Distribution of Incomplete Gastric Intestinal Metaplasia (GIM) Subtype among Biopsy Sites according to the Updated Sydney System and Its Association with GIM Extension

BACKGROUND: Current guidelines recommend that extensive gastric intestinal metaplasia (GIM) be considered as a high-risk marker for the development of gastric cancer (GC). But there is emerging evidence that the incomplete GIM subtype is also a high-risk marker. AIMS: To evaluate the performance of biopsy sites according to the updated Sydney system on detecting the incomplete GIM subtype and to assess its association with GIM extension. PATIENTS AND METHODS: A cross-sectional study was conducted on 280 Vietnamese patients with nonulcer dyspepsia. Biopsy specimens were taken from gastric sites according to the updated Sydney system, and sections were routinely stained with Giemsa and hematoxylin and eosin. Biopsy specimens with intestinalization were further evaluated for GIM subtypes with alcian blue 2.5 and periodic acid Schiff stainings. Two experienced pathologists jointly examined all the specimens and reached consensus. RESULTS: The rates of patients with GIM and the incomplete GIM subtype were 81 (28.9%) and 24 (8.4%), respectively. There was no GIM in specimens taken from the greater curvature of corpus. The proportions of the incomplete GIM subtype detected at the incisura angularis, lesser curvature of corpus, lesser curvature of antrum, and greater curvature of antrum were 34.3% (12/35), 34.5% (10/29), 40.5% (17/42), and 31.6 (6/19), respectively, which were not significantly different (p = 0.89). The presence of an incomplete GIM subtype was associated with multifocal GIM (i.e., ≥3 out of 5 biopsy sites with GIM) (OR = 4.02, CI 95%, 1.33–12.16, p = 0.022) and extensive GIM (i.e., GIM in specimens from both of corpus and antrum) (OR = 2.89, CI 95% 1.04–8.02, p = 0.045). CONCLUSIONS: The proportions of an incomplete GIM subtype were not significantly different among gastric biopsy sites with intestinalization. The association between an incomplete GIM subtype and GIM extension, therefore, may be due to an sum accumulation effect.