► Cowden Syndrome is a rare hereditary cancer syndrome, which confers an increased risk of breast, thyroid, endometrial and colon cancer. ► Atypical polypoid adenomyoma does not generally represent a premalignant lesion, but must be carefully screened for foci of malignancy. ► Cancer screening must be intensified for patients who meet the diagnostic criteria for Cowden Syndrome.
Keywords: Atypical polypoid adenocarcinoma; Cowden Syndrome; Endometrial cancer.