Signet ring cell carcinoma arising from a solitary juvenile polyp in the colon.

Juvenile polyps are relatively common polyps that affect predominantly young patients and may occur in isolated, multiple, and/or familial forms. They have been considered to be benign lesions without neoplastic potential, but for patients with multiple juvenile polyposis, the cumulative malignant risk is greater than fifty percents. In patients with a solitary polyp, the risks are minimal, and only a few cases of malignant change from a solitary juvenile polyp have been reported. We describe the case of a twenty one year old female with one solitary juvenile polyp, which contained a signet ring cell carcinoma in the mucosal layer.