Gynecology · Uterine Fibroids

What Do Hybrid FIGO 2-5, 3-5, or 2-6 Uterine Fibroids Mean?

At a Glance

Hybrid FIGO 2-5, 3-5, and 2-6 labels describe a single transmural uterine fibroid that reaches from the inner lining toward the outer surface. The numbers map its cavity and outer-wall involvement; treatment depends on symptoms, anatomy, and pregnancy goals.

If your MRI or ultrasound report says you have a “hybrid” FIGO fibroid—such as a 2-5, 3-5, or 2-6—it simply means you have a transmural fibroid. This is a single, benign (non-cancerous) fibroid that spans across the thickness of the uterine wall, connecting the inner lining (endometrium) to the outer surface (serosa). The hybrid label is an anatomical map, not a cancer stage or a severity score ^[1]. The first number describes how the fibroid affects the inside of your uterus, and the second number describes how it affects the outside. Having a hybrid fibroid does not automatically mean you need surgery; management depends on your symptoms and goals ^[2].

While our main guide introduces standard FIGO locations, hybrid fibroids require special attention because their involvement in two anatomic compartments directly impacts your symptoms and your treatment options.

Decoding the Hybrid Numbers

The FIGO system categorizes fibroids on a scale of 0 to 8 based on where they sit in the uterus ^[1]. When a fibroid grows large enough to cross through multiple zones and touch both the inside and outside of the uterus, it is given a hyphenated hybrid label ^[3]:

The First Number (Inner Wall): The first number indicates how the fibroid interacts with the inside of your uterus. A 2 or 3 means the fibroid touches or protrudes into your inner uterine cavity. This inner contact may be associated with heavy menstrual bleeding or fertility challenges, especially if the fibroid distorts the cavity ^[4].
The Second Number (Outer Wall): The second number shows how far the fibroid extends toward the outside. A 5 or 6 means the fibroid pushes through the uterine muscle and bulges out of the outer surface. This outer bulge can press on surrounding organs, causing “bulk” symptoms like pelvic pressure, bloating, or frequent urination ^[1].

Here is a breakdown of what specific hybrid labels mean ^[1]:

Hybrid Label	Inside (Endometrial) Relationship	Outside (Serosal) Relationship
FIGO 2-5	Type 2: Protrudes into the cavity (≥50% of the fibroid is in the muscle)	Type 5: Bulges out of the uterus (≥50% of the fibroid is in the muscle)
FIGO 3-5	Type 3: Touches the inner lining but does not protrude into the cavity (100% in the muscle on this side)	Type 5: Bulges out of the uterus (≥50% of the fibroid is in the muscle)
FIGO 2-6	Type 2: Protrudes into the cavity (≥50% of the fibroid is in the muscle)	Type 6: Bulges mostly outside the uterus (<50% of the fibroid is in the muscle)

Why This Matters for Your Treatment

The hybrid label provides a map, but it doesn’t lock you into a single treatment. Your doctor will evaluate the fibroid’s overall size, the depth of the healthy muscle tissue around it, how much it distorts the cavity, and the total number of fibroids you have ^[2]^[5]. Options include:

Observation & Medications: If you have mild or no symptoms, observing the fibroid is reasonable. Medications (like oral contraceptives or tranexamic acid) can help control heavy bleeding and may temporarily shrink some fibroids, but they do not permanently remove the fibroid ^[2].
Hysteroscopic Surgery: Myomectomy (fibroid removal) from the inside (hysteroscopy) uses a camera passed through the vagina. It is often used for cavity-distorting fibroids. However, for a transmural fibroid, a hysteroscopy can generally only remove the inner-protruding portion. Because the fibroid extends deep into the muscle, attempting to remove the entire mass from the inside carries a risk of incomplete removal, fluid-related complications, or puncturing the uterus (perforation) ^[6]^[7]. Your surgeon may recommend a staged or combined approach ^[6]. (Note: FIGO 3-5 lesions have no cavity protrusion, so hysteroscopy is usually not the primary route).
Laparoscopic or Open Surgery: Removing a full-thickness fibroid often requires approaching it from the outside through small keyhole incisions (laparoscopy) or a larger abdominal incision (open myomectomy) ^[2]. Because the fibroid goes all the way through the muscle, the surgeon must carefully stitch and repair the uterine wall. While this reconstruction helps restore the uterus, it leaves a scar and does not eliminate future pregnancy risks, such as uterine rupture ^[8]. Individualized obstetric counseling is necessary to discuss if a future C-section would be advised.
Minimally Invasive Procedures: Uterine artery embolization (UAE) uses a catheter via a small arterial puncture to block blood flow to the fibroid, shrinking it. HIFU uses focused ultrasound energy to destroy fibroid tissue. These are non-surgical alternatives to myomectomy, but they are not suitable for every size or location ^[9]. If future pregnancy is your priority, UAE requires careful counseling, as it may impact fertility or pregnancy outcomes compared to surgery ^[7].

Safety Note: Regardless of your fibroid type, seek prompt medical care if you experience very heavy bleeding that causes severe dizziness or fainting, sudden severe pelvic pain, or if you suspect you might be pregnant. Your clinician may also need to check your blood count for anemia.

Common questions in this guide

What does “hybrid FIGO fibroid” mean?

A hybrid FIGO fibroid is one benign fibroid that extends through the thickness of the uterine wall, from the inner lining toward the outer surface. The first number describes its relationship to the uterine cavity, and the second describes its extension toward the outside of the uterus. It is an anatomical description, not a cancer stage or severity score.

What does a FIGO 2-5 uterine fibroid mean?

A FIGO 2-5 fibroid protrudes into the uterine cavity, with at least half of the fibroid still within the uterine muscle on that side. It also bulges toward the outside of the uterus, with at least half remaining in the muscle on the outer side. This combination may contribute to heavy bleeding, pelvic pressure, or both, although symptoms vary.

How are FIGO 3-5 and FIGO 2-6 fibroids different?

A FIGO 3-5 fibroid touches the inner uterine lining without protruding into the cavity and bulges outward with at least half of the fibroid in the muscle. A FIGO 2-6 fibroid protrudes into the cavity and extends mostly outside the uterus, with less than half in the muscle on the outer side. These distinctions help clinicians plan treatment.

Can hysteroscopy remove a hybrid uterine fibroid?

Hysteroscopy may remove the portion of a hybrid fibroid that protrudes into the uterine cavity, but a transmural fibroid extends deeply through the uterine muscle. Removing the entire mass from inside the uterus may be incomplete and can increase the risk of fluid-related complications or uterine perforation. Depending on the anatomy, a staged or combined procedure, laparoscopy, or open myomectomy may be considered.

Do hybrid uterine fibroids always need surgery?

No. If symptoms are mild or absent, observation may be reasonable, and medications can help control heavy bleeding without permanently removing the fibroid. If treatment is needed, options may include myomectomy, uterine artery embolization, or HIFU, depending on the fibroid’s size, location, cavity distortion, number of fibroids, and your goals.

Can a hybrid fibroid affect fertility or future pregnancy?

A hybrid fibroid that distorts the uterine cavity may be associated with fertility challenges. Full-thickness myomectomy requires repair of the uterine wall, which leaves a scar and does not eliminate the future risk of uterine rupture. Individualized obstetric counseling can address pregnancy planning and whether a cesarean delivery may be advised.

When should I seek urgent care for symptoms from a uterine fibroid?

Seek prompt medical care for very heavy bleeding with severe dizziness or fainting, sudden severe pelvic pain, or a possible pregnancy. A clinician may also check your blood count for anemia and evaluate whether urgent treatment is needed.

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Related questions

When is Heavy Bleeding from Uterine Fibroids an Emergency? When Should I Have MRI, SIS, or Hysteroscopy for Fibroids? Can Uterine Fibroids Cause Fatigue and Shortness of Breath? When Is Severe Uterine Fibroid Pain or Fever an Emergency? Can Uterine Fibroids Cause Painful Sex or Sexual Changes?

Can Fibroids Cause Abdominal Enlargement or Weight Gain? Do I Need an Endometrial Biopsy for Fibroid Bleeding? Does Rapid Fibroid Growth Mean Uterine Cancer? Signs to Know How Is Postmenopausal Bleeding Evaluated With Fibroids? How Are Cavity-Distorting Fibroids Treated Before IVF? What Blood Tests Are Needed for Anemia From Fibroids? Do Uterine Fibroids Become Cancerous or Raise Cancer Risk? Can Fibroids Cause Constipation, Bloating or Urinary Issues? Can Asymptomatic Uterine Fibroids Be Safely Left Untreated? Do Uterine Fibroids Run in Families? Screening Advice Do Uterine Fibroids Shrink Before or After Menopause? Can Diet, Exercise, or Supplements Shrink Fibroids? How Are Fibroids Distinguished from Other Pelvic Conditions? Why Are Fibroids More Common and Severe in Black Women?

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Curated prompts to bring to your next appointment.

1.Could hysteroscopy remove any of the cavity component, would it be a staged procedure, and what would remain afterward?
2.Did this fibroid distort my uterine cavity on the MRI, or does it merely touch the lining without protruding?
3.How will the depth of this fibroid and the required uterine wall repair affect my future pregnancy plans and delivery method?
4.Given the size and number of my fibroids, what are the risks and benefits of an abdominal versus laparoscopic approach for me?

References (9)

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This page explains hybrid FIGO uterine fibroid labels for informational purposes only and does not constitute medical advice. Your gynecologist can interpret your imaging and discuss treatment based on your symptoms and pregnancy plans.