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Introduction

Prevalence of endometrial polyp in the general population is about 24%. Endometrial polyps are more common in postmenopausal women [1-5]. Measurement of endometrial thickness by transvaginal ultrasound is an accepted initial diagnostic modality to distinguish between benign and pathological endometrial changes both before and after menopause. Endometrial cells may be seen in Pap test, although Pap is not the screening test for endometrial cancer. CA-125 may be used in patients with abnormal endometrial bleeding to detect endometrial carcinoma [6].

Literature suggests up to 8% risk of malignant transformation of an endometrial polyp, with the risk higher in postmenopausal women, especially if they present with bleeding and have large polyps [6-12]. Other risk factors for malignant transformation of endometrial polyps are hypertension an obesity [13].

A most recent updated practice guideline for the management of endometrial polyp recommended mandatory histopathological evaluation of the polyp due to the risk of malignancy. In case of atypical hyperplasia or carcinoma of a polyp, hysterectomy is recommended in all post-menopausal patients and in premenopausal patients who do not plan to become pregnant.

Asymptomatic endometrial polyps in postmenopausal women are recommended to be removed in case of large diameter (>2cm) or in patients with risk factors for endometrial carcinoma. Removal of asymptomatic polyps in premenopausal women should be considered in patients with risk factors for endometrial cancer [14].

Although polyps with endometrioid endometrial carcinoma may be completely removed during hysteroscopy, prediction of residual disease is not possible [15].

Material and Method

We received IRB approval for our study. We searched our data base from January 1, 2007 to December 31, 2018 and found 598 cases with endometrial polyps. Ten of these polyps (0.017%) had an associated malignancy. We evaluated the demographic information from the patients and reviewed the pathology glass slides.

Results

The patients with polyps were between 22 and 88-years-old (mean age of 55-years-old), while the patients with malignancy were between 51 to 79-years-old (mean age of 64-years-old). All of the patients, but one was obese (Chart 1). The only patient with BMI of 19 had BMI of 32 three years prior to her presentation. The patients presented primarily with post-menopausal bleeding. One patient did not have a Pap test. Pap tests in four patients were reported as negative for intraepithelial lesion or malignancy (NILM), one had atrophy and the rest had either atypical glandular cells (AGUS) or atypical endometrial cells. One of the patients received Tamoxifen for her breast carcinoma 10 years prior to her current presentation. CA125 was available only in 3 patients and was mildly elevated in one patient. Elevated CA125 may be followed for evaluation of recurrence. Seven patients had serous carcinoma, two were diagnosed with endoemtrioid endometrial adenocarcinoma and one had clear cell carcinoma (Figures 1-2). Size of polyps were between 1 to 3 cm in diameter. Malignancy was confined to polyps in only two patients. Two patients decided to receive treatment in other hospitals, while the other eight underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy with or without staging. One of the cases with diagnosis of serous carcinoma in biopsy had carcinosarcoma (MMMT) in the hysterectomy specimen (table). The patients with endometrioid carcinoma have the best prognosis.

Discussion

Endometrial polyp is relatively common and has a 24% prevalence in the general population. The pathogenesis of endometrial polyp is not well known, although it is believed to be affected by unbalanced estrogen therapy, estrogen-like effect and unbalanced estrogen and progestins. Many estrogen mimics are produced by plants (phytoestrogens) and may behave as estrogen agonists. Recently, a case of a giant endometrial polyp due to the use of phytoestrogens in the daily routine diet for a long time has been reported [16].

Spontaneous endometrial polyp regression has been reported in women younger than 45, premenopausal women, small polyps (<2cm) and abnormal uterine bleeding [17]. The risk factors associated with malignant transformation varies and depends on patient’s menstrual status. In perimenopausal women, polycystic ovary syndrome, polyp volume larger than 10 ml and increase polyp number are risk factors for malignant transformation [18]. Another study suggested that hysterscopic polypectomy should be offered to women with risk factors to allow a reliable histologic evaluation. Hysterectomy should be recommended in the presence of atypical hyperplasia even after complete resection [19].

It has been shown that intraepithelial serous carcinoma has an unfavorable outcome even if the primary tumor is limited to the polyp and can metastasize without atypical invasive growth [20]. Although it was believed that there might be an association between this malignancy and Tamoxifen or breast cancer [21], further studies shown that the genetic factors like Lynch syndrome are responsible for increased risk of developing endometrial cancer [22-26].

Obesity seems to become a more prominent risk factor in postmenopausal women with an endometrial polyp. A recent study showed that the thickness of periperitoneal fat is a predictor of malignancy in overweight and obese women with endometrial polyp [27]. Another study showed that the body shape index (ABSI), which evaluated abdominal adiposity, correlates with the presence of endometrial cancer/atypical hyperplasia. Both ABSI and BMI z scores might potentially be associated with endometrial carcinoma [28].

Postmenopausal bleeding is an alarming symptom that should be evaluated. Presence of endometrial cells in Pap tests in postmenopausal women, especially if they are atypical should be followed by an endometrial biopsy.

Limited number of patients in this study is its weakness, which requires further studies to confirm the finding. Current or remote history of obesity in all the patients is the strength of this study.  Endometrial polyps in postmenopausal women, especially if it is symptomatic should be followed closely, especially in obese women.

Conflicts of Interest

The author has no conflict of interest and the article is not under consideration for publication elsewhere. This paper received no funding from any funding agency in the public, commercial or not-for-profit sectors.

This project was presented in a talk in the 3rd World Congress on Cancer Biology and Immunology. March 11-12, 2019. Milan, Italy