Endometriosis is a condition where tissue similar to the lining of the uterus, known as the endometrium, grows outside the uterine cavity. This misplaced tissue can develop on various organs within the pelvis and, less commonly, in other parts of the body. When this endometrial-like tissue accumulates, it can form growths or “masses,” a specific manifestation of this chronic condition.
What is an Endometriosis Mass?
Endometriosis masses are collections of endometrial-like tissue that respond to hormonal changes during the menstrual cycle. Like the uterine lining, these growths thicken, break down, and bleed. Since the blood has no way to exit the body, this causes inflammation, pain, and can lead to scar tissue and adhesions that bind organs together. These masses are benign, or non-cancerous, growths.
One common type of endometriosis mass is an endometrioma, often referred to as a “chocolate cyst.” These cysts form on the ovaries and are filled with dark, thick, reddish-brown fluid that resembles melted chocolate, old menstrual blood and tissue. They can affect one or both ovaries and vary in size, ranging from 2 to 20 centimeters.
Another form of endometriosis mass is deep infiltrating endometriosis (DIE), where lesions penetrate more than 5 millimeters into the peritoneal tissue, lining the abdominal cavity. These can form hard nodules or clumps of scar tissue in deeper tissues such as the bowel, bladder, or rectovaginal septum. Superficial peritoneal implants are another type of lesion; while often small, they can coalesce into larger masses.
Symptoms and Locations
Endometriosis masses can develop in various locations within the pelvic area, with the ovaries being a frequent site for endometriomas. Other common locations include the fallopian tubes, the outer surface of the uterus, the broad ligaments, the rectovaginal septum, and the cul-de-sac (the space behind the uterus). Less commonly, masses can affect the bowel, bladder, ureters, or distant sites like the lungs.
Symptoms often correlate with the location of the mass. Chronic pelvic pain is a common symptom, often severe and debilitating, and it may worsen before and during menstrual periods. Masses located on or near the rectovaginal septum or bowel can cause painful bowel movements, known as dyschezia, or rectal bleeding during menstruation. If a mass affects the bladder, individuals may experience painful urination (dysuria) or blood in the urine during their period.
Deep pain during sexual intercourse, known as dyspareunia, is another symptom associated with endometriosis masses. Heavy or prolonged menstrual bleeding (menorrhagia) or bleeding between periods can also occur. Infertility can result from anatomical distortion or inflammation from these masses, affecting reproductive organ function. Large masses can lead to symptoms like bloating or abdominal distension, and many individuals experience fatigue.
Diagnosis and Treatment
Diagnosing endometriosis masses begins with a thorough review of symptoms and medical history, including questions about pelvic pain, menstrual patterns, and any difficulties with fertility. A physical examination, including a pelvic exam, may reveal tenderness, nodules, or palpable masses; however, small lesions may not be detectable.
Imaging techniques help identify larger masses. Transvaginal ultrasound is a primary tool for detecting endometriomas, appearing as characteristic “ground glass” cysts on the ovaries. Magnetic Resonance Imaging (MRI) offers more detailed images, useful for mapping deep infiltrating endometriosis and surgical planning. However, imaging alone cannot definitively confirm endometriosis.
The gold standard for a definitive diagnosis of endometriosis, including masses, is laparoscopy. This minimally invasive surgical procedure involves a small incision near the navel to insert a slender viewing instrument, a laparoscope. The surgeon can then directly visualize pelvic organs and identify endometrial-like tissue. A biopsy of suspicious tissue can be taken for microscopic examination to confirm the diagnosis, and often, the surgeon can treat it during the same procedure.
Treatment for endometriosis masses is individualized, considering symptoms, mass location, and patient goals like fertility preservation. Medical management often involves pain relievers like NSAIDs to alleviate symptoms. Hormonal therapies, such as birth control pills, progestins, or GnRH agonists, are used to suppress the growth of endometrial-like tissue by regulating hormonal cycles. While these therapies can manage symptoms and prevent further growth, they do not remove existing masses.
Surgical management focuses on mass removal. Excision, or cutting out, masses is a common approach, usually performed laparoscopically. In some severe cases, a laparotomy, involving a larger incision, may be necessary, particularly for extensive scar tissue or deep infiltrating lesions. Surgical removal aims to alleviate pain, improve fertility, and restore normal anatomical relationships. Skilled surgeons are important for complete excision of masses while preserving surrounding tissues.
Endometriosis Masses and Cancer Risk
Endometriosis masses are benign and non-cancerous. However, there is a slightly increased, though low, lifetime risk of developing certain types of ovarian cancer in individuals with endometriosis, particularly those with endometriomas. This association is primarily with clear cell and endometrioid ovarian carcinoma.
Studies indicate individuals with endometriosis may have a four-fold greater risk of ovarian cancer compared to those without the condition. For more severe forms, such as deep infiltrating endometriosis and ovarian endometriomas, the risk can be higher, potentially increasing to nearly ten times the risk. This does not mean endometriosis transforms into cancer, but rather that certain genetic or cellular changes might occur in a small percentage of cases over many years.
Given the low overall incidence of ovarian cancer, even an increased relative risk translates to a minimal absolute risk. Regular follow-ups with healthcare providers are important for monitoring, especially for larger or changing endometriomas. Most endometriosis masses are not cancerous. This information should encourage informed discussions with medical professionals rather than cause undue alarm.