Uterine fibroids are common, non-cancerous growths that develop in the uterus. They are almost always benign and do not cause cancer.
Understanding Uterine Fibroids
Uterine fibroids, also known as leiomyomas or myomas, are non-cancerous growths composed of smooth muscle cells and fibrous connective tissue. They can vary in size from microscopic to large masses that can distort the uterus. Fibroids are common, affecting an estimated 70% to 80% of women by age 50. Many women with fibroids do not experience symptoms, leading to incidental diagnoses during routine pelvic exams or imaging studies.
Fibroids can develop in different locations within the uterus. Submucosal fibroids grow into the uterine cavity, intramural fibroids develop within the muscular wall of the uterus, and subserosal fibroids extend to the outer surface of the uterus. Their composition and growth pattern distinguish them from malignant growths, as fibroid cells do not exhibit the uncontrolled, invasive behavior characteristic of cancer cells.
Fibroids and Cancer
Benign fibroids do not become cancerous. The confusion often arises due to a rare type of uterine cancer called leiomyosarcoma, which can initially present with similar symptoms or appearance. Leiomyosarcoma is an aggressive cancer that originates from the smooth muscle cells of the uterus, but it is a distinct disease from its inception.
Leiomyosarcoma is an extremely rare condition, occurring in approximately 0.35 to 0.64 per 100,000 women in the United States each year. While a leiomyosarcoma might be mistaken for a fibroid before surgery, particularly if it grows rapidly, it does not develop from an existing benign fibroid. These cancerous tumors are characterized by abnormal and uncontrolled cellular growth, which can invade surrounding tissues and potentially spread to distant parts of the body.
The average age for diagnosis of uterine leiomyosarcoma is around 51 years. Black women tend to have uterine leiomyosarcomas twice as often as White women, though the overall incidence remains very low across all groups. Differentiating between a benign fibroid and a leiomyosarcoma before surgery can be challenging due to similar symptoms and imaging characteristics.
Recognizing Symptoms and Seeking Care
While uterine fibroids are benign, they can cause a range of symptoms that impact a woman’s quality of life. Common symptoms include heavy or prolonged menstrual bleeding, pelvic pressure or pain, frequent urination, and constipation. The severity of these symptoms often depends on the size, number, and location of the fibroids.
If new, severe, or concerning symptoms arise, consult a healthcare professional. A doctor can diagnose fibroids through a pelvic exam, which may reveal an enlarged or irregularly shaped uterus. Imaging techniques such as ultrasound are often used to confirm the presence, size, and location of fibroids. Seeking medical advice for persistent symptoms ensures proper evaluation and management.