Endometrial polyps are localised overgrowth of the basal stroma with central blood vessels covered by surface endometrium mostly rising from the fundal area. Recent reports suggested clonal rearrangement of stromal chromosome 6p21 as the initial step triggering the development of polyps.
They could be seen in 10-15% of all women and could be associated with endometrial hyperplasia. They are rarely seen during teenage years. Their incidence increases with age to peak between 40 - 50 years before gradually declining after the menopause.
Polyps could be single or multiple, small or large, sessile or pedunculated, symptomatic or asymptomatic. In approximately 20% of cases they are multiple and in less than 1% are associated with malignancy. So polyps are typically single, small, asymptomatic and benign. However occasionally they cause:
postcoital bleeding
intermenstrual bleeding
heavy menstruation
vaginal discharge
postmenopausal bleeding especially in women on HRT.
This list shows that abnormal bleeding episodes to be the most important presenting problem related to endometrial polyps. In fact a previous study showed that 25% of all abnormal pre-and-postmenopausal bleeding to be caused by endometrial polyps. Accordingly polyps should be included in the provisional diagnosis of such cases and appropriate means taken to exclude them.
Ultrasonically a polyp could be seen as an echogenic mass splitting the central echo of a midcycle trilaminar endometrium. Otherwise they are best delineated with some fluid instilled into the cavity. On the other hand a fibroid disturbing the uterine cavity would be seen pushing the midline endometrium echo to one side rather than splitting it. Occasionally reversing colours could make a pathology more prominent as shown by the polyp below.
An echogenic polyp splitting the central echo of a midcycle trilaminar endometrium
Reversed colour (negative) of the same polyp in the previous picture gave better resolution.
Fibroid pushing the central endometrial echo to one side rather than splitting it. The presence of a feeding vessel is not indicative of a polyp in this case.
However ultrasonic examination could fail to reveal endometrial polyps as they are usually echogenic and merge with the background echogenicity of the endometrium. Sometimes they show few anechoic areas due to entrapped mucous. Each polyp has central blood vessels which could be seen with colour Doppler mapping.
Endometrial polyp with entrapped mucous seen as hypoechoic areas
Multiple polyps easily demarcated after instilling small amount of fluid in the cavity
Tamoxifen treatment for breast cancer could also stimulate the growth of multiple large polyps. However few of these ultrasonically diagnosed multiple polyps were shown by saline infusion sonohysterography to be subendometrial cysts which resolved after suspending tamoxifen medication.
Once a diagnosis is established a polyp could be removed hysteroscopically either with a grasping forceps or better still using a resectoscope if it had a broad base. The best time for carrying hysteroscopy is just after menstruation is finished. This would exclude the risk of missing a polyp within a thick endometrium as expected later on during the cycle.
The two pictures above show endometrial polyps being removed using a resectoscope or grasping forceps respectively
Blind D&C is no longer a valid operative option to remove polyps. A polyp could be pushed in front or sideway by the curette missing it altogether. The removed polyp should be examined histologically to exclude any malignant changes.
The issue relating endometrial polyps to infertility or repeated miscarriages is a sticky one. Small polyps are not expected to have such an effect. However larger ones occupying a significant part of the cavity or obstructing tubal ostia and symptomatic ones should be removed. This is especially so if no other cause has been demonstrated during other investigations. We also remove any polyp before starting assisted reproductive treatment.
Endometrial polyp rising from within the ostium of the left tube. This could obstruct that tube leading to a fertility problem
