© Georg Thieme Verlag KG Stuttgart · New York
Use of proton pump inhibitors may cause squamous epithelial masking of intramucosal carcinoma in Barrett's esophagus
18 April 2007 (online)
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 ). 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 ). 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 ). 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 ). 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 ).
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     . 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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K. Tanaka, MD
Department of Endoscopic Medicine
Mie University School of Medicine
Tsu, Mie Prefecture 514-8507