RESUMO
The histological distinction between Barrett's esophagus involving the distal esophagus and intestinal metaplasia of the stomach has important clinical implications and can be difficult even with the use of histochemical stains. Cytokeratin (CK) 7 and 20 are cytoplastic structural proteins that show restricted expression in normal and malignant epithelia of the gastrointestinal tract. CK7 and 20 immunostaining were performed on a 67-year-old male with cardiac cancer with reflux esophagitis due to sliding hernia. The CK7/20 immunoreactivity pattern of cancer and reflux esophagitis in this case showed superficial CK20 staining and strong CK7 staining of both superficial and deep glands. In intestinal metaplasia of the stomach, strong CK20 immunostaining in superficial and deep glands and absent CK7 immunoreactivity were noted. Neither CK7 nor CK20 immunoreactivity was noted in squamous cell epithelium. Therefore, we concluded that in this patient intestinal metaplasia of the esophagus was BE. The CK7/20 reactivity pattern is useful for identifying the intestinal metaplasia of the esophagus from the stomach using histological materials from biopsy and surgically resected specimens.