We present here a rare case of intramucosal carcinoma arising in Barrett’s esophagus,
but masked with squamous epithelium because of administration of a proton pump inhibitor.
A 70-year-old man underwent gastrointestinal endoscopy as a follow-up examination
of gastroesophageal reflux disease. Endoscopy showed an erythematous irregular mucosa
with white plaques, covering a quarter of the circumference in the right side on the
squamo-columnar junction (Figure [1]). Histopathologically, the biopsy specimen of the lesion revealed an adenocarcinoma.
Esophagectomy was proposed, but it was refused by the patient. Because the inflammation
of the lesion might be too severe to perform endoscopic mucosectomy, the patient was
started on 20 mg rabeprazole daily.
Figure 1 Endoscopy showed an erythematous irregular mucosa in the right side on the squamo-columnar
junction (arrows).
Five weeks after starting the proton pump inhibitor, endoscopy showed marked improvement
of the inflammation (Figure [2]). Most of the lesion was covered with squamous epithelium, and the demarcation was
unclear. The endoscopic image using acetic acid instillation revealed more clearly
that the tumor was covered with squamous epithelium (Figure [3]). Endoscopic ultrasonograpy showed that the lesion was confined to the mucosal layer.
We performed an endoscopic mucosectomy, and the lesion was completely resected en
bloc without complication.
Figure 2 Five weeks after starting administration of a proton pump inhibitor, endoscopy showed
that the lesion was mildly erythematous, and the inflammation had improved. Most of
the lesion was covered with squamous epithelium, and the demarcation was unclear (arrows).
Figure 3 The endoscopic image using acetic acid instillation revealed more clearly that the
tumor was covered with squamous epithelium (arrows).
The resected specimen showed that the lesion was in the iodine-staining mucosa (Figure
[4]). Histopathologically, the lesion was diagnosed as a well-differentiated adenocarcinoma
limited to the mucosa, and most of the tumor was covered with squamous epithelium
(Figure [5]).
Figure 4 The resected specimen showed that the lesion was in the iodine-staining mucosa (arrows).
Figure 5 High-magnification microscopic images show well-differentiated adenocarcinoma beneath
the squamous epithelium (H&E, × 100).
Intestinal metaplasia, dysplasia, or carcinoma in Barrett’s esophagus can be replaced
by squamous epithelium after endoscopic treatment associated with acid suppression
therapy [1]
[2]
[3]
[4]
[5]. However, it has not been reported previously that acid suppression alone could
lead to squamous re-epithelialization over a carcinoma in Barrett’s esophagus. Thus
the use of proton pump inhibitors should be monitored carefully because they may cause
masking of a small carcinoma in Barrett’s esophagus.
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