Extremely well-differentiated tubular adenocarcinomas (EWDAs) of the stomach are characterized
by surface maturation and their mimicking of intestinal metaplasia. Endoscopically,
intramucosal EWDAs are frequently ill defined with indistinct borders due to the pallor
of the neoplastic mucosa and the lack of contrast against the background atrophic
and metaplastic mucosa. We evaluated the effectiveness of endoscopic resection for
EWDAs after endoscopic submucosal dissection (ESD).
Among 872 patients with early gastric cancer, 17 EWDAs were identified (1.9 %). Endoscopically,
the flat or depressed type was significantly more common among EWDAs (88.2 %) than
among early gastric cancers of other histologies (37.8 %; P < 0.01). The discrepancy between endoscopically estimated tumor size and tumor size
as confirmed in pathology reports was significantly greater among EWDAs (18.4 ± 22.0 mm)
than among others (5.8 ± 7.5 mm). Involvement of the lateral resection margin was
more common (29.4 % vs. 2.5 %; P < 0.05), and complete resection was achieved less often in EWDAs (47.1 % vs. 80.4 %;
P = 0.01) compared to the others.
EWDAs are associated with higher rates of incomplete resection after ESD, especially
along the lateral margins. Pathologists should alert endoscopists when this diagnosis
is made, with its associated risks; and endoscopists should pay particular attention
to the extent of these tumors during resection.
