Fibroids vs. Cysts: What’s the Difference?

Fibroids are solid, noncancerous growths in the uterus, while cysts are fluid-filled sacs that develop in or on the ovaries, both potentially causing pelvic discomfort and other symptoms.

Within the realm of women’s health, the terms “fibroids” and “cysts” are often mentioned in passing, and sometimes, occur concurrently. While they may sound similar, fibroids and cysts are entirely different in nature — one is a solid tumour-like growth in the uterus, while the other is a fluid-filled sac that develops in the ovaries. 

The confusion often comes from the fact that both can develop silently, without obvious symptoms, or they can cause discomfort, changes in menstrual patterns, and, in some cases, complications.

In this article, we’ll break down everything you need to know about uterine fibroids and ovarian cysts — their differences, symptoms, diagnosis, and treatment options — so that you can make informed decisions about your health. Whether you’re facing a recent diagnosis, dealing with unexplained symptoms, or simply want to be proactive about your gynaecological health, understanding these conditions can empower you to take control of your well-being.

What Are Uterine Fibroids?

Uterine fibroids are noncancerous growths that develop in or on the uterus, which affect many women at some point in their lives. These growths — also known as leiomyomas or myomas — are composed of muscle and fibrous tissue and can vary greatly in size. Some remain as small as a seed, while others can grow large enough to distort the shape of the uterus.

Although the vast majority of fibroids are benign, their impact ranges from unnoticed to significantly disruptive. Some women may have fibroids without experiencing symptoms, while others may struggle with severe menstrual bleeding, period cramps, or even fertility complications. Whether the fibroids result in significant symptoms depend on both their sizes and locations. 

Types of Uterine Fibroids

The location of fibroids within the uterus plays a key role in how they affect the body. The three primary types are:

• Intramural Fibroids — the most common type, these grow within the muscular wall of the uterus. Small intramural fibroids can sometimes result in no symptoms; larger ones can cause heavy periods and/or pelvic discomfort as they expand [1]. 

• Submucosal Fibroids — develop just beneath the lining of the uterus and extend into the uterine cavity [2]. Even small submucosal fibroids can lead to excessive menstrual bleeding and fertility issues.

• Subserosal Fibroids — grow on the outer surface of the uterus. They typically can grow fairly large before they start resulting in symptoms, whereby they can sometimes press against adjacent organs like the bladder or intestines, leading to frequent urination or constipation [3].

Common Symptoms of Uterine Fibroids

While some fibroids remain asymptomatic, others can cause a range of symptoms depending on their size and location. The most common signs include:

• Heavy and prolonged menstrual bleeding — fibroids can cause periods that last longer than usual or are excessively heavy, sometimes leading to (iron-deficiency) anaemia.

• Pelvic pain and pressure — larger fibroids can create a sensation of fullness or pressure in the lower abdomen, leading to chronic discomfort.

• Frequent urination — fibroids pressing against the bladder may cause an increased urge to urinate.

• Constipation or bloating — subserosal fibroids that press against the intestines can disrupt digestion, causing bloating or difficulty passing stool or gas.

• Difficulty in conceiving/ pregnancy complications — depending on their location/size, fibroids can cause difficulty in conceiving or pregnancy complications 

• (Rarely) Deep vein thrombosis (DVT) – should the uterus be grossly enlarged with multiple/sizable fibroid(s), vascular complications such as a DVT can result due to the fibroid uterus compressing on pelvic vessels 

For many women, fibroids remain a silent condition, only discovered during routine gynaecological exams or health screening checks. However, if you experience symptoms that begin to interfere with daily life, it’s best to consult your gynaecologist for early diagnosis and management.

What Are Ovarian Cysts?

Ovarian cysts are fluid-filled sacs that develop in or on the ovaries. They are a common occurrence in women of reproductive age and, in many cases, remain harmless, causing no symptoms and disappearing on their own. However, some cysts grow larger, persist, or cause discomfort, leading to concerns about their impact on reproductive health and overall general health/ well-being.

Unlike uterine fibroids (which are solid growths of muscle and fibrous tissue), ovarian cysts are usually filled with fluid and can form due to various reasons. While most are benign, certain types may indicate underlying conditions that require medical intervention.

Types of Ovarian Cysts

Ovarian cysts are broadly classified into two main categories:

• Functional Cysts — the most common type, these form as part of the normal menstrual cycle, are considered physiological and typically resolve on their own. All women in their reproductive lifespan will typically get these in their lifetimes. They include:

• Follicular cysts — occur when a follicle fails to release an egg and continues to grow. These typically resolve after a few menstrual cycles and are harmless.

• Corpus luteum cysts — this is a cyst that forms following ovulation (egg release), which produces progesterone in preparation for potential pregnancy. It can sometimes take a few menstrual cycles to fully resolve, and rarely may result in complications such as bleeding, causing transient pain. 

• Pathological Cysts — unrelated to the menstrual cycle, these cysts develop due to abnormal cell growth and may require medical attention. They include:

• Dermoid cysts — formed from embryonic cells, containing tissue like hair, fat, or even teeth.

• Endometriomas — caused by endometriosis, where uterine tissue grows outside the uterus and attaches to the ovaries, often leading to pain, distortion of pelvic anatomy, and fertility issues.

• Cystadenomas — fluid-filled cysts that develop on the ovarian surface and can grow quite large.

• Cancerous cysts – these are rare but are known to grow rapidly in size/ progress quickly with minimal symptoms. They commonly also have mixed solid-cystic areas within the cysts instead of being purely fluid-filled. 

Common Symptoms of Ovarian Cysts

Many ovarian cysts remain asymptomatic and are only discovered during routine pelvic examinations. However, when they become problematic, they can cause a variety of symptoms, including:

• Pelvic pain — ranging from a dull ache to sharp, sudden pain, particularly if a large cyst ruptures, bleeds or twists, termed as an “ovarian cyst accident”. 

• Bloating or a feeling of fullness — larger cysts can cause abdominal discomfort or a sensation of heaviness/bloatedness.

• Irregular menstrual cycles — some cysts interfere with normal ovulation, leading to unpredictable periods.

• Pain during intercourse — cysts that exert pressure on surrounding tissues may cause discomfort or deep pain during sex.

• Difficulty in conceiving — depending on their type, some ovarian cysts e.g. endometriomas can result in decreased ovarian reserve/function and therefore cause difficulty in conceiving. 

• Frequent urination or bowel issues — larger cysts can press against the bladder or intestines, leading to urinary urgency or constipation.

In rare cases, an ovarian cyst may rupture, bleed or become twisted (ovarian torsion). These situations require immediate medical attention. In cases of acute, severe pain, which can sometimes also be associated with nausea, fever etc, particularly if one has a known history of ovarian cyst, it is recommended to get evaluated at the nearest Accident and Emergency Department as urgent surgical intervention may sometimes be required before irreversible ovarian function loss occurs. 

Cysts And Fibroids Are Vastly Different

Although both are common gynaecological conditions, they differ in structure, location, and how they affect the body. Fibroids are solid growths that develop in or on the uterus, while cysts are fluid-filled sacs that form in or on the ovaries. Their causes, symptoms, and treatment approaches also vary.

While some women may have both conditions at the same time, proper diagnosis through medical evaluation is essential to determine the most ideal course of action for managing symptoms and maintaining reproductive health. 

The table below provides a clear comparison to help differentiate between the two:

While fibroids tend to develop slowly and may grow large before causing noticeable symptoms, ovarian cysts often come and go undetected. However, both conditions require medical evaluation if they cause persistent discomfort, affect menstrual cycles, or lead to fertility concerns.

Are Cysts or Fibroids Cancerous?

Most fibroids and cysts are benign, non-cancerous growths. In fact, many ovarian cysts resolve on their own, especially in premenopausal women. 

However, in rare cases, certain forms of cysts, like complex ovarian cysts or rapidly growing fibroids, may raise some concern for malignancy. This is why it’s important to monitor these growths through regular check-ups with your doctor. 

How Are Fibroids and Cysts Diagnosed? 

The first step to treating your condition starts with an understanding of your condition. An accurate diagnosis is essential for distinguishing between fibroids and ovarian cysts, as their symptoms can sometimes overlap. While some women may not experience any noticeable signs, others may struggle with persistent pelvic pain, abnormal bleeding, or changes in their menstrual cycle. 

Medical History and Physical Examination

Your gynaecologist may ask about:

• The duration and severity of menstrual bleeding
• The presence of pelvic pain, bloating, or pressure
• Changes in urinary or bowel habits
• Family history of fibroids or ovarian conditions

A physical examination, including a pelvic exam, helps detect any abnormalities in the uterus or ovaries. If a mass is present, further imaging tests are usually recommended to confirm the diagnosis and assess its characteristics.

Imaging Tests

To accurately identify whether a growth is a fibroid or a cyst, healthcare providers rely on imaging tests, including:

• Ultrasound — the most commonly used diagnostic tool, ultrasound helps visualise both fibroids and cysts. A transabdominal ultrasound (performed over the abdomen) or a transvaginal ultrasound (inserted into the vagina for a closer view) can reveal the size, shape, and location of the growth. A transvaginal ultrasound is typically preferred over that of a transabdominal approach due to its proximity to the pelvic organs.

• MRI (Magnetic Resonance Imaging) — provides more detailed images, particularly useful for fibroids. MRI scans help distinguish fibroids from other uterine conditions and determine the most suitable course of treatment.

• Additional Tests — in some cases, further testing may be necessary to rule out complications or underlying conditions:

• Blood Tests — women with heavy bleeding due to fibroids may be tested for anaemia and/or iron deficiency, which occurs when excessive blood loss reduces red blood cell levels.

• Ovarian tumor marker blood tests e.g. CA-125  — used when a complex ovarian cyst is detected, blood tests such as tumor marker panels can measure CA-125 protein levels [4], which can be elevated in cases of ovarian cancer, endometriosis, or other conditions. However, an elevated CA-125 level does not necessarily indicate cancer (as it can also be raised in many benign or non-gynaecological conditions), and additional testing may be required for a definitive diagnosis.

Early detection helps prevent complications and allows for timely medical intervention for your symptoms. 

How Do You Treat Fibroids and Cysts? 

The management of fibroids and ovarian cysts depends on their size, symptoms, and potential complications. While many cases require only monitoring, others may need medical or surgical intervention. Below are the primary treatment approaches for both conditions.

Treatment for Fibroids

Not all fibroids require immediate treatment—many are small, asymptomatic, and discovered incidentally during routine gynaecological exams. For those that cause symptoms, the following options are available:

• Observation — small, asymptomatic fibroids are often monitored through regular check-ups and imaging scans. If they do not grow or cause discomfort, no further treatment is necessary.

• Medications — these range from non-hormonal medications (such as tranexamic acid/NSAIDs aka non-steroidal anti-inflammatory drugs, which can help alleviate heavy menstrual bleeding/menstrual cramps when taken on an as needed basis) to hormonal therapy, including birth control pills, progesterone-based treatments, or gonadotropin-releasing hormone (GnRH) agonists, can help reduce heavy bleeding, and alleviate symptoms [5]. However, these treatments do not eliminate nor shrink fibroids (other than GnRH injections, which can only be used for the short-term and hence does not serve to shrink fibroids effectively in the long-term). 

• Minimally Invasive Procedures — for women experiencing significant symptoms but wanting to avoid major surgery, procedures like uterine artery embolization (UAE) [6] or microwave ablation (Ierardi AM, Savasi V, Angileri SA, Petrillo M, Sbaraini S, Pinto A, Hanozet F, Marconi AM, Carrafiello G. Percutaneous High Frequency Microwave Ablation of Uterine Fibroids: Systematic Review. Biomed Res Int. 2018 Jan 8;2018:2360107. doi: 10.1155/2018/2360107. PMID: 29511672; PMCID: PMC5817312.) can reduce fibroid size and symptoms by blocking their blood supply or using heat to destroy fibroid tissue. These, however, are usually temporalizing and typically do not have long-term efficacy and a proportion of women may ultimately require repeated procedures, hence precise case selection is required to determine suitability. 

• Surgical Options — for severe cases, surgery may be required:

• Myomectomy — Myomectomy removes fibroids while preserving the uterus, making it a preferred choice for women who wish to maintain fertility.

• Hysterectomy — Hysterectomy involves removing the uterus entirely and is considered a definitive solution for recurrent or large fibroids in women who do not plan future pregnancies.

Treatment for Ovarian Cysts

Many ovarian cysts, particularly functional cysts, resolve on their own within a few menstrual cycles. However, when cysts persist, grow larger, or cause severe symptoms, treatment may be necessary.

• Observation — functional cysts that are small and asymptomatic typically resolve naturally. Regular ultrasound monitoring ensures that they do not grow or develop complications.

• Medications — hormonal medications, such as birth control pills or progesterone-only medications, help prevent the formation of new functional cysts by regulating ovulation or suppressing ovarian activity. They can also sometimes shrink the size of existing ovarian cysts (depending on the nature). 

• Surgical Intervention — when a cyst becomes large, persistent, or causes significant symptoms, surgical removal may be required:

• Cystectomy — Cystectomy removes only the cyst while preserving the ovary, which is ideal for benign cysts.

• Oophorectomy — Oophorectomy removes the affected ovary if the cyst is large, complex, or suspected to be cancerous [8]. This option is considered when necessary to prevent complications.

Surgical intervention for an ovarian cyst has the potential to reduce one’s ovarian reserve and hence proper preoperative counseling is necessary for you to understand the implications of surgery and whether or not it is necessary for your case. 

When to Visit a Gynaecologist

While many cases of fibroids and ovarian cysts do not cause serious issues, certain symptoms indicate the need for prompt medical evaluation. Seek immediate medical attention if you experience:

• Severe or persistent pelvic pain — sudden, sharp pain may indicate a ruptured cyst or ovarian torsion, both of which require urgent care.

• Heavy or prolonged menstrual bleeding — excessive blood loss from fibroids can lead to anaemia, causing fatigue, dizziness, and weakness.

• Significant bloating or abdominal swelling — a rapidly growing fibroid or cyst may cause noticeable changes in the abdomen, warranting further investigation.

• Pain during intercourse — persistent discomfort can be a sign of fibroids pressing on surrounding organs or cysts affecting the ovaries.

• Changes in urination or bowel habits — frequent urination, constipation, or difficulty emptying the bladder may be due to large fibroids pressing against the bladder or intestines.

• Unexplained weight changes or hormonal changes — symptoms like sudden weight changes, irregular periods, or excessive hair growth should not be overlooked.

Summary

Fibroids and ovarian cysts are two of the most common gynaecological conditions, yet they remain widely misunderstood. Many women only learn about them after experiencing symptoms like pelvic pain, heavy bleeding, or irregular periods. Others may have them without knowing, as these growths can sometimes develop silently. While fibroids and cysts share some similarities, they are fundamentally different in structure, causes, and the way they affect reproductive health.

Hopefully this quick guide helped shed some light on their differences, what to expect for each condition, and when to seek medical attention. If you’re experiencing unexplained pelvic pain, irregular periods, or other concerning symptoms, it is imperative to seek a gynaecologist’s opinion for a detailed diagnosis and personalised treatment plan.

References