Uterine fibroids, also known as leiomyomas or myomas, are non-cancerous muscular tumors that grow within the walls of the uterus. These growths are common, affecting up to 80% of women by age 50, and are almost always benign. While fibroids can cause a wide range of uncomfortable symptoms, they rarely constitute an immediate life threat. The potential severity of a fibroid depends heavily on its exact location and size.
Understanding Location and Type
A subserosal fibroid is defined by its location on the outer surface of the uterus, developing beneath the serosa, the uterus’s smooth outer layer. Because they grow outward into the pelvic cavity, these fibroids typically do not affect the uterine lining responsible for menstrual bleeding. This outward growth pattern means subserosal fibroids are less likely to cause heavy or prolonged menstrual bleeding than other types.
Subserosal fibroids can be attached to the uterus in two main ways. They may have a broad base, known as a sessile attachment, or they can be attached by a thin cord-like structure called a peduncle, making them a pedunculated subserosal fibroid. The difference in attachment dictates potential complications and the type of symptoms a person may experience.
Addressing the Risk of Cancer and Acute Complications
The risk of malignancy in a subserosal fibroid is extremely low. Fibroids are benign, and the chance of one transforming into a cancerous tumor, called leiomyosarcoma, is estimated to be less than 0.1%. Leiomyosarcoma generally arises spontaneously, rather than from a pre-existing fibroid, and is a distinct, aggressive form of cancer.
The main acute complication specific to the subserosal type is torsion, which is the twisting of the stalk of a pedunculated fibroid. Torsion is a rare event, but it cuts off the fibroid’s blood supply, leading to severe, sudden-onset abdominal pain. This condition is a surgical emergency due to the risk of tissue death and subsequent peritonitis. Prompt surgical intervention is necessary to remove the compromised tissue.
Chronic Symptoms and Organ Pressure
The major impact of subserosal fibroids on a person’s quality of life stems from chronic pressure symptoms rather than immediate danger. As these fibroids grow outward, they occupy space in the pelvis and press on adjacent organs. For instance, a large fibroid located near the front of the uterus can press on the bladder, leading to symptoms like frequent urination or difficulty emptying the bladder completely.
If a subserosal fibroid is positioned toward the back of the uterus, it can push against the rectum or large intestine. This pressure interferes with normal bowel function, causing chronic constipation or a feeling of pelvic fullness and bloating. Large fibroids can also cause persistent lower back pain or leg pain by pressing on nerves in the pelvic region.
While subserosal fibroids typically do not interfere with conception, a very large fibroid can sometimes complicate a pregnancy. They may restrict the space available for fetal growth or potentially affect the birth process. These chronic, bulk-related symptoms are often what compel a person to seek treatment.
When and How Treatment is Required
Most subserosal fibroids that are small and cause no symptoms are managed with watchful waiting and routine monitoring. Intervention is generally reserved for fibroids that cause significant chronic symptoms that disrupt daily life or for the rare occurrence of an acute complication like torsion. The severity of the symptoms, the fibroid’s size, and the patient’s desire for future pregnancy determine the treatment pathway.
Surgical removal, known as myomectomy, is often the preferred treatment for symptomatic subserosal fibroids, as it removes the growth while preserving the uterus. This procedure can often be performed using minimally invasive laparoscopic or robotic techniques, especially for pedunculated or moderately sized subserosal fibroids. Less commonly, non-surgical options like Uterine Fibroid Embolization (UFE) or Magnetic Resonance-guided Focused Ultrasound (MRgFUS) may be considered, but myomectomy remains the most effective way to eliminate the source of pressure symptoms.