Incorporate Histologic Subtyping of Gastric Intestinal Metaplasia Into Routine Practice
Vanessa M. Shami, MD, FASGE reviewing Shah SC, et al. Gastroenterology 2019 Dec 6.
Gastric cancer is the third leading cause of cancer-related mortality worldwide, with over 780,000 deaths in 2018 alone. While there are endoscopic protocols for colorectal and esophageal preneoplastic lesions, endoscopic protocols for gastric neoplasia have not been clearly established in the U.S. This paper encourages clinicians to consider incorporating histologic subtyping into routine clinical practice, as it may alter endoscopic surveillance of gastric intestinal metaplasia (GIM).
The progression of GIM without dysplasia to malignancy is estimated at 12.4 (95% confidence interval [CI], 10.7-14.3) per 10,000 person-years’ time. Moreover, a recent meta-analysis has suggested there was an associated 3.33-fold (95% CI, 1.96-5.64) higher risk of gastric cancer progression in individuals with incomplete GIM compared to complete GIM. The differentiation of complete and incomplete GIM subtypes can be performed by hematoxylin and eosin stain. Complete GIM is classically characterized by well-developed goblet cells interspersed between columnar cells and Paneth cells at the base of crypts, while incomplete GIM does not have a characteristic brush boarder and goblet cells of variable size. If the pathologist is unable to distinguish between these types of GIM, then special stains may be used (ie, Alcian blue [AB] pH 2.5/periodic acid-Schiff [PAS]). The AB/PAS stain costs an additional $20 and categorizes GIM as type I (complete GIM) and type II/III (subclasses of incomplete GIM) by assessing various acid mucins.
Comment:
Differentiating incomplete versus complete GIM may assist with standardization of endoscopic surveillance protocols for gastric preneoplasia and improve data research efforts for finding consensus on histopathologic protocols and definitions.
Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.
Vanessa M. Shami, MD, FASGE
Citation(s):
Shah SC, Gawron A, Mustafa R, Piazuelo MB. Histologic subtyping of gastric intestinal metaplasia: overview and considerations for clinical practice. Gastroenterology 2019 Dec 6. (Epub ahead of print) (https://doi.org/10.1053/j.gastro.2019.12.004)
