What are chance of malignancy for endometrial polyp?

The risk of malignancy associated with endometrial polyps is generally low but clinically significant, especially in certain high-risk groups.

Studies report that malignant transformation within endometrial polyps occurs in approximately 5.8% of polyps without atypia and increases up to around 20.5% in polyps with atypical histology. This risk is notably higher in women with abnormal immunohistochemical markers such as p53 overexpression and loss of PTEN expression, which are associated with an increased risk of malignant neoplasia within the polyp Abrão et al. 2018.

Additional factors that increase the likelihood of malignancy in endometrial polyps include advanced age, abnormal uterine bleeding, and higher body mass index. Women carrying genetic syndromes such as Lynch syndrome are also at elevated risk. However, other factors such as the number or size of polyps, diabetes, hypertension, or family history remain inconclusive based on current evidence Koblížková et al. 2024.

In clinical practice, the overall rate of endometrial carcinoma found in specimens with polyps varies but can be identified in around 6% of symptomatic postmenopausal women undergoing hysteroscopy, with the risk rising with age and presence of atypical histology Zhu et al. 2026. The use of immunohistochemical markers (p53 and PTEN) has shown promise in stratifying malignant risk and may guide closer follow-up or more aggressive management.

While UK clinical guidelines on gynaecological cancers acknowledge that endometrial polyps may harbor malignant or premalignant lesions, they emphasize the importance of prompt investigation of abnormal uterine bleeding and appropriate referral for definitive diagnosis and treatment, reflecting the above risk factors.NICE CKS,NICE NG12

In summary, though the majority of endometrial polyps are benign, a malignant transformation risk estimated between approximately 5% to 20% in certain subgroups justifies careful evaluation, especially in postmenopausal women, those with abnormal bleeding, advanced age, and/or atypical histological features Abrão et al. 2018Koblížková et al. 2024Zhu et al. 2026.NICE CKS,NICE NG12