BACKGROUND & AIMS: Subsquamous intestinal metaplasia (SSIM) has been observed after endotherapy in patients
with neoplastic Barrett’s esophagus (BE). However, it is not clear whether SSIM occurs in untreated
patients. Incompletely eradicated SSIM could provide a source of recurrent disease. We
assessed its prevalence in a large cohort of patients who had not received endoscopic therapy.
METHODS: Two experienced pathologists analyzed 138 samples of 506 resection specimens found to contain
squamous epithelium from 110 patients with neoplastic BE treated by widespread endoscopic
mucosal resection (92 men; mean age, 66 years). The maximum extent of SSIM was measured.
RESULTS: Of the 138 samples analyzed, 124 (89.9%) were found to contain SSIM from 108 of the 110
patients (98.2%). The mean length of SSIM was 3.3 mm (range, 0.2–9.6 mm; 25% ‡5 mm); SSIM
length correlated with BE length (P < .05). In 83 of 138 samples (60.1%), the SSIM consisted
partially or entirely of neoplasias of different grades, with a mean subsquamous extension of
3.3 mm; the extension correlated with grade of neoplasia (P [ .0001).
CONCLUSIONS: Most patients with BE with neoplasia (of all grades) have subsquamous extension of intestinal
metaplasia, including subsquamous extension of lesions at the squamocolumnar junction.
Therefore, biopsy and resection of neoplastic BE should extend at least 1 cm into the squamous
epithelium.