Adenoma of the rectum with multiple foci of signet-ring cell carcinoma

Abstract
A case with multiple foci of signet-ring cell carcinoma in an adenoma of the rectum is presented. Four foci of the signet-ring cell carcinoma and four foci of the common type of adenocarcinoma were found independently in a large polypoid tumor. An originating point of one of the signet-ring cell cancer foci was shown by an extensive serial sectioning study.