Confusion often arises between fibroids and cysts, as both are growths that can occur in the female reproductive system. While they share some overlapping symptoms and are frequently benign, fibroids and cysts are distinct conditions with different origins, compositions, and typical locations. Understanding these differences helps recognize their characteristics and implications.
What Are Fibroids?
Fibroids are non-cancerous growths composed of smooth muscle cells and fibrous connective tissue that develop within or on the walls of the uterus. These growths, also known as uterine leiomyomas or myomas, are common among women of childbearing age. It is estimated that 70% to 80% of women may experience fibroids by age 50, though many do not have symptoms.
Fibroids can vary in size, ranging from as small as a seed or pea to as large as a grapefruit. They can occur as a single growth or in clusters, and their size can fluctuate, sometimes growing, shrinking, or remaining stable. Their location within the uterus can also vary, including intramural (within the uterine wall), subserosal (on the outside surface), or submucosal (just beneath the uterine lining).
What Are Cysts?
Cysts are fluid-filled sacs. In the female reproductive system, the most common type confused with fibroids are ovarian cysts, which develop on or inside the ovaries. These cysts are common, especially in women who have not yet gone through menopause.
Most ovarian cysts are benign and often resolve on their own. Many form as a natural part of the menstrual cycle, known as functional cysts. For example, a follicular cyst can develop if a follicle, which normally releases an egg, fails to rupture and continues to fill with fluid. Another type, a corpus luteum cyst, forms when the empty follicle seals itself after releasing an egg, causing fluid to accumulate inside.
Distinguishing Fibroids from Cysts
Distinguishing fibroids from cysts involves recognizing their differences in location, composition, and symptoms. Fibroids are primarily found in the uterus, growing within its muscular walls or on its outer or inner surfaces. Cysts are most commonly found on or within the ovaries.
In terms of composition, fibroids are solid masses made of dense muscle and fibrous tissue, giving them a firm, hard texture. In contrast, cysts are typically fluid-filled sacs, though some less common types can contain other materials like hair, skin, or fatty tissue. This difference in internal structure is a distinguishing factor.
Both conditions can cause shared symptoms such as pelvic pain or pressure, abdominal bloating, and discomfort during sex. However, fibroids are more commonly associated with heavy or prolonged menstrual bleeding, which can sometimes lead to anemia. Ovarian cysts, particularly if they are large or rupture, are more likely to cause sharp or dull abdominal pain, often localized to one side. They may also lead to irregular menstrual periods.
The exact causes of fibroids are not fully understood, but they are believed to be influenced by hormones like estrogen and progesterone, as well as genetic factors. Ovarian cysts, especially functional ones, primarily arise from the normal process of ovulation during the menstrual cycle. Diagnosis often involves a pelvic exam and imaging techniques. Ultrasound is commonly used to differentiate between solid fibroids and fluid-filled cysts, and an MRI can provide more detailed information about size and location.
Treatment approaches differ based on the condition. Many small, asymptomatic fibroids and cysts may only require watchful waiting. For symptomatic fibroids, management can include hormonal therapies, medications to manage symptoms, or surgical procedures ranging from myomectomy (removal of fibroids) to hysterectomy (removal of the uterus). Non-invasive procedures like uterine fibroid embolization (UFE) are also options. Ovarian cysts are often initially managed with hormone therapy, such as birth control pills to prevent new cyst formation, and larger or problematic cysts may require surgical removal (cystectomy) or, in some cases, removal of the ovary (oophorectomy).
When to Consult a Doctor
While many fibroids and cysts are benign and do not cause symptoms, certain signs warrant medical evaluation. Consult a healthcare professional if you experience severe or sudden pelvic pain, persistent abdominal bloating or enlargement, or heavy and prolonged menstrual bleeding. Other concerning symptoms include bleeding between periods, difficulty emptying your bladder, or new or worsening pain during intercourse. A professional diagnosis is important for determining the underlying cause of your symptoms and guiding appropriate management.