Endometrial polyps are areas of growth of endometrial tissue inside the uterine cavity. They are composed of stroma, glands and blood vessels coated by endometrial lining. Polyps are the most common endometrial pathology found on diagnostic hysteroscopy and represent a frequent cause of operative hysteroscopy. They are usually benign in nature, although, when symptomatic, about 20% have small areas of hyperplasia being between 0.5% and 1% malignant.
Endometrial polyps are classified as follows:
1-Functional polyps (20%): with similar histologic appearance to normal endometrium with secretory or proliferative changes. They are subdivided into glandular and fibrous, according to the predominant tissue.
2-Hyperplastic (35%): with histologic changes similar to those found in endometrial hyperplasia.
3-Atrophic (44%): with regressive or atrophic changes. These polyps are usually found in menopausal patients.
4-Malignant (1%): with the presence of cancer cells in the polyp.
There are two concepts that require special attention. The “Malignancy of a polyp” and the “pseudo-polyp”. The malignancy of a polyp, refers to polyps with the presence of malignant cells but the base of the polyp as well as the rest of the uterine cavity are completely normal. The term “pseudo-polyp” refers to thickened areas endometrial polypoid like tissue, less than 1 cm in size that disappears after menstruation because they have no nutritive vessels to support them.