Endometrial polyps are growths of tissue that form in the inner lining of the uterus, known as the endometrium. These growths consist of an overgrowth of endometrial glands and supportive tissue that projects into the uterine cavity. They are typically noncancerous, but the most common symptom leading to their discovery is abnormal uterine bleeding. This bleeding can present as heavy menstrual flow, spotting between periods, or vaginal bleeding after menopause. Because abnormal bleeding can also signal more serious conditions, such as endometrial hyperplasia or cancer, an accurate diagnostic process is necessary to identify the cause and rule out malignant changes.
Initial Assessment and Screening
The diagnostic process begins with a detailed medical history and a physical examination to understand the patient’s specific symptoms. The clinician will inquire about the nature of the bleeding, including its timing, duration, and volume, to determine if the pattern suggests the presence of polyps. A standard gynecological exam, including a speculum and bimanual exam, is performed to rule out other structural or cervical causes of bleeding.
Following the physical assessment, the first-line imaging test is typically a Transvaginal Ultrasound (TVUS). This procedure involves placing a slender device into the vagina that uses sound waves to create an image of the uterus. The doctor examines the image for any thickening of the endometrial lining or the presence of a focal mass, which may indicate a polyp.
For premenopausal women, TVUS is ideally performed in the early part of the menstrual cycle, immediately after bleeding stops, when the endometrial lining is at its thinnest. This timing helps to reduce the chance that the normal, proliferative thickening of the endometrium is mistaken for a polyp. Although TVUS is an excellent initial screening tool, it often cannot definitively distinguish a polyp from other structures like a small submucosal fibroid or generalized endometrial thickening. Therefore, if the TVUS is inconclusive or the clinical suspicion remains high, a more specialized imaging technique is required to clarify the findings.
Specialized Imaging Techniques
When the initial TVUS does not provide a clear picture, the next step is Saline Infusion Sonography (SIS), also known as Hysterosonography. This enhanced ultrasound technique significantly improves the visualization of the uterine cavity and is highly sensitive for detecting and characterizing intrauterine masses like endometrial polyps.
The procedure involves threading a thin catheter through the cervix, after which a sterile saline solution is gently introduced into the uterine cavity. The fluid distends the endometrial cavity, separating the inner walls and creating a dark, fluid-filled background. Against this backdrop, a polyp, which is a solid tissue growth, stands out clearly as a bright structure.
SIS allows the clinician to determine specific features of the suspected polyp, such as its size, exact location, and whether it is attached by a broad base or a thin stalk. This fluid contrast is helpful for distinguishing a polyp, which arises from the endometrial layer, from a submucosal fibroid, which originates from the deeper muscle wall of the uterus. SIS offers a high degree of diagnostic accuracy before moving to a surgical procedure.
Definitive Visualization and Pathology
The gold standard for both definitive diagnosis and often simultaneous treatment is Hysteroscopy. This procedure involves inserting a thin, lighted telescope, called a hysteroscope, through the vagina and cervix directly into the uterus. Hysteroscopy provides the physician with a direct, magnified view of the entire uterine cavity, allowing for the precise confirmation of the polyp’s presence, size, and attachment site.
During the hysteroscopy, the physician can visually confirm the characteristics of the growth, such as its color and surface texture, which offers clues about its nature. Hysteroscopy is not just diagnostic; it is also therapeutic, as specialized instruments can be passed through the scope to remove the polyp completely, a procedure known as hysteroscopic polypectomy.
Whether the polyp is removed entirely or a tissue sample is taken, the final step is sending the specimen to a laboratory for pathological examination. The pathologist examines the tissue to confirm that the growth is a benign endometrial polyp and, most importantly, to rule out any precancerous changes or malignant cells. The pathology report provides the definitive diagnosis, ensuring that any potential for endometrial hyperplasia or cancer is identified and addressed.