A case of gastric hyperplastic polyp with malignant transformation.

In this paper we report a case of hyperplastic polyp with malignant transformation. The patient was followed up by annual radiographic and endoscopic examination during 9 years. The first gastroscopy revealed a semi-pedunculated polyp beneath the esophageal-cardiac junction, 1.5cm in diameter and slightly reddish with smooth surface. Histological findings showed a hyperplastic polyp. There was slight change in size, but no change in histological examination of the lesion during the follow-up. In 1996, the biopsy specimen showed an atypical epithelium and the polyp was removed by snear polypectomy. A microscopic examination revealed a well-differentiated adenocarcinoma. Immunohistochemically, p53 and Ki-67 immunostaining showed positive in the carcinoma portion of the adenocarcinoma bearing a hyperplastic polyp in the stomach.