Clinicopathologic features of colorectal gastric heterotopia.

Gastric heterotopia of the colorectum is rare, and its clinicopathologic spectrum and diagnostic pitfalls remain incompletely characterized. We retrospectively reviewed colorectal gastric heterotopia diagnosed at a single institution from June 2003 through January 2024. Three pathologists independently reviewed the available histologic material, and clinical, endoscopic, ancillary-study, and follow-up data were collected from existing records. Ten cases were identified. Patients ranged from 18 to 78 years of age; six were male and four were female. Four patients were asymptomatic, four presented with gastrointestinal bleeding, and two with nonspecific abdominal pain. All lesions were solitary; eight involved the rectal/anorectal region, and seven were polypoid. Among seven lesions with documented size, the median was 1.2 cm (range, 0.7-3.0 cm). All cases contained well-developed oxyntic glands with parietal and chief cells; foveolar epithelium was present in 9, pyloric glands in 6, goblet cells in 3, and minor salivary gland-type tissue in 1. Tissue identification testing in two detached-fragment cases showed genotype concordance between gastric-type mucosa and native colorectal reference tissue, supporting same-patient origin. No dysplasia or neoplasia was identified. Clinical follow-up was available for eight patients (median, 63 months); persistent gastric heterotopia was documented in one patient, with no dysplasia or malignancy identified during follow-up. These findings expand the clinicopathologic spectrum of this rare lesion and show generally favorable findings during the available follow-up.