Uterine Leiomyoma: A Comprehensive Review of Etiology, Classification, Clinical Presentation, and Management

-- ALL -- General Surgery Gynecology Robotic Surgery Urology WLH

Gynecology / Feb 4th, 2026 11:59 am A⁺ | a^-

BASIC INFORMATION:

Date & Time:

18 July 2024 | 14:30 IST

Lecture Handout Prepared from the Teaching Session by: Dr. R. K. Mishra

SUMMARY:

This comprehensive lecture provides an in-depth review of uterine leiomyomas (fibroids) for postgraduate surgical and gynecological trainees. It covers the full spectrum of the condition, from etiology and pathogenesis to clinical management. The lecture establishes that leiomyoma is the most common benign solid tumor in the female reproductive system, originating from a single myometrial smooth muscle cell and driven primarily by estrogen. It outlines the key risk factors (e.g., nulliparity, obesity, early menarche) and protective factors (e.g., multiparity, smoking). The content systematically classifies fibroids based on their anatomical location, detailing the intramural, subserosal, and submucosal types, and explains the standardized FIGO classification system for fibroid mapping. The lecture further explores the pathological features, including the characteristic whorled appearance and the various secondary degenerative changes, with a focus on red (carneous) degeneration in pregnancy and the rare but critical sarcomatous transformation. Clinical manifestations are detailed, correlating symptoms like menorrhagia, infertility, and pressure effects with fibroid location. Finally, the lecture outlines the diagnostic pathway, emphasizing transvaginal sonography (TVS) as the primary investigative tool, and provides a structured management algorithm that encompasses expectant management, a wide range of medical therapies, interventional radiology procedures, and definitive surgical options like myomectomy and hysterectomy.

KEY KNOWLEDGE POINTS:

Etiology, pathogenesis, and risk factors of uterine leiomyoma, highlighting its monoclonal origin and estrogen dependency.
Anatomical classification (intramural, subserosal, submucosal) and the clinical application of the FIGO classification system.
Gross and microscopic pathology, including the false capsule and the whorled appearance.
The six types of secondary changes in fibroids, with a focus on hyaline degeneration, red (carneous) degeneration, calcification, and sarcomatous change.
The spectrum of clinical symptoms, including the pathophysiology of abnormal uterine bleeding, subfertility, and pressure symptoms.
Complications of fibroids during pregnancy, labor, and the postpartum period.
Diagnostic evaluation, including the roles of physical examination, transvaginal sonography (TVS), saline infusion sonohysterography (SIS), MRI, and hysteroscopy.
A structured management protocol, detailing expectant, medical, interventional (UAE, MRgFUS), and surgical (myomectomy, hysterectomy) treatment options based on symptoms and patient factors.

INTRODUCTION:

Uterine leiomyoma, colloquially known as a fibroid, is the most common benign solid neoplasm of the uterus and the female body. Arising from the myometrium, these tumors are composed of smooth muscle and fibrous connective tissue. Their growth is fundamentally influenced by the hormonal milieu, particularly estrogen. While a majority of leiomyomas are asymptomatic, they can present with a wide array of clinical manifestations, including abnormal uterine bleeding, pelvic pain, infertility, and pressure symptoms, significantly impacting a patient's quality of life. A comprehensive understanding of their etiology, classification, pathology, and clinical presentation is essential for accurate diagnosis, effective patient counseling, and the formulation of an appropriate, individualized management strategy. This lecture provides a complete overview, from basic science to clinical practice, to equip trainees with the knowledge required to manage this ubiquitous gynecological condition.

LEARNING OBJECTIVES:

To define uterine leiomyoma, understand its etiology, risk factors, and the hormonal basis of its growth.
To classify leiomyomas based on their anatomical location and apply the FIGO system for clinical and surgical planning.
To describe the gross and microscopic pathology of leiomyomas and identify the various secondary changes they can undergo.
To recognize the clinical symptoms and signs of leiomyomas and correlate them with tumor location and complications.
To outline the investigative pathway for diagnosing and mapping leiomyomas.
To apply a structured algorithm for the management of leiomyomas, encompassing expectant, medical, interventional, and surgical approaches.

CORE CONTENT:

1.0 Etiology, Pathogenesis, and Risk Factors

1.1 Definition and Histogenesis

Terminology:
- Leiomyoma: The correct medical term, from leio (smooth), myo (muscle), and -oma (tumor).
- Fibromyoma: An alternative term reflecting its composition of fibrous and muscle tissue.
- Fibroid: A common layman’s term, considered a misnomer as muscle is the primary component.
Histological Origin: Benign tumors originating from the myometrium, composed of smooth muscle cells and fibrous connective tissue.
Monoclonal Nature: Each leiomyoma arises from the neoplastic transformation of a single smooth muscle cell (myocyte). The initial stimulus for this transformation is unknown.

1.2 Incidence and Epidemiology

Leiomyoma is an exceptionally common condition, affecting approximately 20% of women by age 30.
A significant proportion (up to 75%) of women with leiomyomas remain asymptomatic.

1.3 Risk and Protective Factors

Risk Factors (Associated with Hyperestrogenic States):
- Increasing Age: Incidence rises throughout the reproductive years. They are rare before menarche.
- Early Menarche: Longer cumulative exposure to endogenous estrogen.
- Nulliparity: Uninterrupted ovulatory cycles without the hormonal shifts of pregnancy.
- Obesity: Peripheral conversion of androgens to estrogen in adipose tissue.
- Polycystic Ovary Syndrome (PCOS): Anovulation and unopposed estrogen.
- Family History & Race: Genetic predisposition and higher incidence in Black women.
Protective Factors (Associated with Reduced Estrogen Exposure):
- Multiparity: Pregnancy and lactation are hypoestrogenic states.
- Late Menarche: Shorter duration of lifetime estrogen exposure.
- Menopause: Cessation of ovarian estrogen production leads to regression.
- Combined Oral Contraceptives (COCs): Suppress ovulation and reduce endogenous estrogen.
- Smoking: Nicotine inhibits the aromatase enzyme, lowering estrogen levels.

1.4 Etiology and Pathogenesis

Hormonal Influence: Fundamentally estrogen-dependent tumors. Leiomyoma cells contain higher concentrations of estrogen/progesterone receptors and the enzyme aromatase, which locally converts androgens to estrogen, creating a hyperestrogenic microenvironment that promotes growth.
Genetic Factors: Non-random chromosomal abnormalities, particularly on chromosomes 7 and 12.
Growth Factors: Estrogen is believed to mediate its effects by stimulating growth factors like EGF, IGF, and TGF-β, which promote cell proliferation.

2.0 Classification of Uterine Leiomyomas

2.1 Anatomical Classification

All fibroids begin as an intramural lesion and may grow toward the uterine cavity or serosal surface.

Corporeal Fibroids (arise from the uterine body):
- Intramural (Interstitial): Most common (75%). Located within the myometrium.
- Subserosal (Subperitoneal): 10-15% of cases. Grow outwards toward the serosa.
  - Pedunculated: Develops a stalk.
  - Wandering/Parasitic: Detaches and gains a new blood supply from another structure (e.g., omentum).
  - Intraligamentary (Pseudo Broad Ligament Myoma): Grows sideways into the layers of the broad ligament.
- Submucosal (Submucous): Least common (5%) but most symptomatic. Grow inwards toward the endometrial cavity. Can be sessile (broad-based) or pedunculated (fibroid polyp).
Cervical Fibroids: Rare (1-2%). Arise from the cervix.

2.2 The FIGO Classification System

A standardized system for "fibroid mapping," essential for surgical planning.

Type 0: Pedunculated intracavitary (100% in cavity).
Type 1: Submucosal, <50% intramural extension.
Type 2: Submucosal, ≥50% intramural extension.
Type 3: 100% intramural, but contacts the endometrium.
Type 4: Purely intramural.
Type 5: Subserosal, ≥50% intramural extension.
Type 6: Subserosal, <50% intramural extension.
Type 7: Pedunculated subserosal.
Type 8: Atypical (e.g., cervical, parasitic).
Hybrid (e.g., Type 2-5): A single fibroid spanning from the submucosal to the subserosal layer.

3.0 Pathology and Secondary Changes

3.1 Pathological Features

Gross Appearance: The uterus is often enlarged and distorted. The tumor is firm, with a smooth, whitish, and characteristically whorled cut surface. It is surrounded by a false capsule of compressed myometrium, which creates a key avascular plane for surgical enucleation ("shelling out").
Microscopic Appearance: Composed of interlacing bundles of smooth muscle cells and fibrous connective tissue.

3.2 Secondary Changes

Occur when the fibroid outgrows its blood supply.

Atrophy: Shrinkage due to estrogen withdrawal (e.g., post-menopause).
Degeneration (Most Common):
- Hyaline Degeneration: Most frequent (65%). The central whorled pattern is replaced by a homogeneous, glassy substance.
- Cystic Degeneration: Follows hyaline change, with liquefaction forming cystic spaces. Common post-menopausally.
- Fatty Degeneration: Deposition of fat globules, typically post-menopausally.
- Calcific Degeneration: Deposition of calcium salts, often in postmenopausal women, leading to a "stone hard" fibroid or "womb stone."
- Red (Carneous) Degeneration: An acute vascular event (e.g., vessel thrombosis) seen typically during the second half of pregnancy or puerperium. Presents with acute pain and a tender mass. The cut surface has a dark red, "raw beef" appearance.
Necrosis: Tissue death from severe circulatory compromise (e.g., torsion of a pedicle).
Infection: Occurs when a fibroid is exposed to microorganisms (e.g., a submucous polyp protruding into the vagina).
Vascular Changes: Telangiectasia or lymphangiectasia.
Sarcomatous Change: The most dangerous but rarest change (≈0.1%). Transformation into a malignant leiomyosarcoma. Suspect if there is rapid growth, especially post-menopausally, or recurrence of a fibroid polyp after removal.

4.0 Clinical Presentation and Symptomatology

While 75% are asymptomatic, symptomatic fibroids can cause:

4.1 Abnormal Uterine Bleeding (AUB)

Menorrhagia (Most Common Symptom): Heavy menstrual bleeding, especially with submucous or large intramural fibroids. Mechanisms include:
1. Increased Endometrial Surface Area: A larger shedding surface.
2. Impaired Myometrial Contractility: Failure to constrict spiral arterioles.
3. Vascular Congestion: Venous obstruction by the tumor mass.
4. Endometrial Hyperplasia: Due to a co-existing hyperestrogenic state.
Metrorrhagia (Intermenstrual Bleeding): Often due to ulceration of a submucous fibroid.

4.2 Pain and Pressure Symptoms

Pain: Uncomplicated fibroids are typically painless. Pain suggests a complication like degeneration, torsion, or extrusion of a polyp.
Dysmenorrhea: Can be congestive (dull ache) or spasmodic (colicky pain as the uterus tries to expel a polyp).
Pressure Symptoms:
- Bladder: Urinary frequency or retention (anterior fibroid).
- Rectum: Constipation (posterior fibroid).
- Ureter: A large broad ligament fibroid can compress the ureter, causing hydroureter, hydronephrosis, and rarely, secondary polycythemia.

4.3 Subfertility and Pregnancy Complications

Subfertility: Can result from cornual obstruction of fallopian tubes, distortion of the uterine cavity impairing sperm transport, or a defective implantation site.
Pregnancy Complications: Increased risk of miscarriage, preterm labor, IUGR, red degeneration, dystocia (obstructed labor if fibroid is in lower segment), and postpartum hemorrhage (PPH) due to uterine atony.

5.0 Clinical Evaluation and Investigations

5.1 Clinical Examination

General: Pallor may be present due to anemia from menorrhagia.
Abdominal Examination: A firm, non-tender, mobile (side-to-side) mass arising from the pelvis may be palpable if the uterus is >12-14 weeks size.
Bimanual Pelvic Examination: The uterus feels irregularly enlarged. A key sign is that movement of the cervix is transmitted to the abdominal mass, confirming its uterine origin. This sign may be absent in a pedunculated subserous fibroid.

5.2 Investigations

Transvaginal Sonography (TVS): The gold-standard initial investigation. It accurately determines the number, size, and location of fibroids.
Saline Infusion Sonohysterography (SIS): Superior to TVS for evaluating the endometrial cavity. Involves instilling saline to delineate intracavitary pathology, differentiating submucous fibroids from endometrial polyps.
Hysteroscopy: Allows direct visualization and simultaneous resection ("see and treat") of submucous fibroids and polyps.
Magnetic Resonance Imaging (MRI): Provides superior soft-tissue detail. Used in complex cases, for precise surgical mapping, and to differentiate fibroids from adenomyosis.
Hysterosalpingography (HSG): Primarily used in the workup of infertility to assess tubal patency and identify cavity-distorting lesions ("filling defects").
Endometrial Sampling (Curettage): May be performed in patients with AUB to rule out co-existing endometrial hyperplasia or carcinoma before conservative surgery.

6.0 Management of Uterine Leiomyoma

Management must be individualized based on symptoms, age, and fertility desires.

6.1 Expectant Management (Watchful Waiting)

Indication: Asymptomatic fibroids in a uterus <12 weeks in size.
Protocol: Regular clinical and sonographic follow-up every 6 months.

6.2 Medical Management (Temporizing Measure)

Aims to control symptoms, correct anemia, or bridge to surgery/menopause.

GnRH Analogs (Agonists/Antagonists): Create a hypoestrogenic state, reducing fibroid size and vascularity preoperatively. Use is limited to 3-6 months due to menopausal side effects (osteoporosis risk); "add-back therapy" is needed for longer use.
Selective Progesterone Receptor Modulators (SPRMs - Ulipristal Acetate): Effectively reduce fibroid volume and bleeding.
Antiprogestins (Mifepristone): Reduces fibroid size but carries a risk of endometrial hyperplasia with long-term use.
Levonorgestrel-Releasing IUS (LNG-IUS): Effective for menorrhagia if the uterine cavity is not significantly enlarged or distorted.
Other agents: Tranexamic Acid (reduces bleeding), NSAIDs (for dysmenorrhea).

6.3 Interventional Radiology

Uterine Artery Embolization (UAE): Polyvinyl alcohol particles are injected to block the uterine arteries, causing avascular necrosis and shrinkage of fibroids. Carries a risk of post-embolization syndrome and premature ovarian failure. Fertility preservation is not guaranteed.
Magnetic Resonance-guided Focused Ultrasound (MRgFUS): Uses focused ultrasound energy to cause thermal ablation of fibroid tissue. Contraindicated in patients desiring future fertility.

6.4 Surgical Management (Definitive)

Myomectomy: Surgical removal of fibroids while preserving the uterus. The treatment of choice for symptomatic women desiring to retain fertility. Can be performed via laparotomy, laparoscopy, or hysteroscopy.
Hysterectomy: Surgical removal of the uterus. Provides a permanent cure.

SURGICAL PEARLS:

During myomectomy, the key to minimizing blood loss is to identify and dissect within the avascular plane of the "false capsule" surrounding the fibroid.
The symptom profile is dictated more by the fibroid's location than its size. A small submucous fibroid can cause more significant bleeding than a large subserous one.
During surgery for a broad ligament fibroid, the ureter's location is critical. In a pseudo broad ligament fibroid (from the uterus), the ureter is displaced laterally. In a rare true broad ligament fibroid, the ureter is located medial to the mass.
While GnRH agonists reduce fibroid size and vascularity, they can obscure the plane of cleavage, making surgical enucleation more challenging.
A rapid increase in the size of a fibroid, especially post-menopausally, is a clinical red flag that warrants investigation to rule out sarcomatous transformation.

COMPLICATIONS AND THEIR MANAGEMENT:

Intraoperative: The primary risk during surgery for cervical or broad ligament fibroids is iatrogenic injury to the ureter.
Early Postoperative:
- Postpartum Hemorrhage (PPH): Fibroids can impair uterine contractility after delivery, leading to atony.
- Post-Embolization Syndrome (after UAE): Characterized by pelvic pain and fever; management is typically supportive.
Late Postoperative:
- Recurrence: Recurrence of a fibroid polyp after excision should raise suspicion for underlying sarcomatous change.
- Amenorrhea/Ovarian Failure: A potential risk following UAE.

MEDICOLEGAL AND PATIENT SELECTION CONSIDERATIONS:

Management must be "patient-tailored," considering age, symptom severity, and reproductive goals. A thorough discussion of all options (expectant, medical, interventional, surgical) is essential for informed consent.
For patients desiring future fertility, myomectomy is the standard of care. Interventions like UAE and MRgFUS are generally not recommended.
The presence of postmenopausal bleeding in a patient with a growing uterine mass is a significant red flag for malignancy (leiomyosarcoma) and requires prompt and thorough evaluation.
Pregnant patients with fibroids must be counseled about potential risks, including miscarriage, preterm labor, IUGR, and an increased likelihood of cesarean section and PPH.

SUMMARY AND TAKE-HOME MESSAGES:

Leiomyoma is the most common benign uterine tumor, with its growth being predominantly estrogen-dependent. Its classification by location (intramural, subserosal, submucous) and the FIGO system dictates its clinical impact and management.
While typically slow-growing, fibroids can undergo secondary changes. Red degeneration is an acute event in pregnancy, while rapid growth, especially post-menopausally, should raise suspicion for leiomyosarcoma (0.1% risk).
Transvaginal sonography is the investigation of choice. Management is individualized: asymptomatic fibroids can be watched, while symptomatic fibroids require treatment tailored to the patient’s desire for uterine preservation.
Medical therapy is a temporizing measure, whereas surgery (myomectomy or hysterectomy) offers definitive treatment.

MULTIPLE CHOICE QUESTIONS (MCQs):

From which uterine layer do leiomyomas originate?

a) Endometrium

b) Serosa

c) Myometrium

d) Perimetrium

Correct Answer: c
Which hormone is primarily implicated in the growth of leiomyomas?

a) Prolactin

b) Testosterone

c) Estrogen

d) Progesterone

Correct Answer: c
According to the FIGO classification, a pedunculated intracavitary fibroid entirely within the endometrial cavity is classified as:

a) Type 0

b) Type 1

c) Type 7

d) Type 8

Correct Answer: a
What is the most common type of degeneration seen in uterine fibroids?

a) Red degeneration

b) Cystic degeneration

c) Calcific degeneration

d) Hyaline degeneration

Correct Answer: d
A 30-year-old pregnant woman at 28 weeks gestation presents with acute, severe abdominal pain and a tender uterine mass. What is the most likely diagnosis?

a) Sarcomatous change

b) Red (carneous) degeneration

c) Calcific degeneration

d) Atrophy of the fibroid

Correct Answer: b
Which is the most common presenting symptom of a symptomatic uterine fibroid?

a) Dysmenorrhea

b) Infertility

c) Menorrhagia

d) Pelvic pain

Correct Answer: c
The "false capsule" of a fibroid, which provides a key surgical plane for enucleation, is formed by:

a) The serosal layer of the uterus

b) Compressed adjacent myometrium

c) Fibrous tissue from the tumor itself

d) A true epithelial lining

Correct Answer: b
Which investigation is considered the gold standard for initial diagnosis of uterine fibroids?

a) MRI

b) Hysteroscopy

c) Transvaginal Sonography (TVS)

d) Hysterosalpingography (HSG)

Correct Answer: c
For a symptomatic patient who desires to preserve her uterus, which is the most appropriate definitive surgical treatment?

a) Hysterectomy

b) Myolysis

c) Myomectomy

d) Uterine artery embolization

Correct Answer: c
A large pseudo broad ligament fibroid can cause hydronephrosis by compressing the ureter. In this condition, the ureter is typically found:

a) Medial to the fibroid

b) Lateral to the fibroid

c) Anterior to the fibroid

d) Encased by the fibroid

Correct Answer: b
What is the primary mechanism of Uterine Artery Embolization (UAE)?

a) Hormonal suppression

b) Thermal ablation of fibroid tissue

c) Occlusion of blood supply causing avascular necrosis

d) Modulation of progesterone receptors

Correct Answer: c
The characteristic macroscopic appearance of a leiomyoma on cut section is:

a) Yellowish, soft, and lobulated

b) Whitish, firm, and whorled

c) Reddish, friable, and necrotic

d) Translucent and cystic

Correct Answer: b
Intermenstrual bleeding (metrorrhagia) in a patient with a fibroid is most commonly associated with:

a) Torsion of a subserous fibroid

b) Ulceration of a submucous fibroid

c) An intramural fibroid compressing vessels

d) Malignant transformation

Correct Answer: b
Which of the following is considered a protective factor against leiomyoma development?

a) Nulliparity

b) Early menarche

c) Obesity

d) Multiparity

Correct Answer: d
Rapid growth of a uterine fibroid in a postmenopausal woman should raise the highest suspicion for:

a) Red degeneration

b) Leiomyosarcoma

c) Calcific degeneration

d) Cystic degeneration

Correct Answer: b
Which investigation is superior to standard TVS for differentiating a submucous fibroid from an endometrial polyp?

a) 3D Ultrasound

b) Saline Infusion Sonohysterography (SIS)

c) Diagnostic Laparoscopy

d) MRI

Correct Answer: b
Prolonged use of mifepristone for fibroid treatment is limited by the risk of:

a) Ovarian failure

b) Endometrial hyperplasia

c) Androgenic side effects

d) Osteoporosis

Correct Answer: b
A fibroid in which location is most likely to cause dystocia during labor?

a) Fundal subserous

b) Upper body intramural

c) Lower uterine segment

d) Pedunculated parasitic

Correct Answer: c
On bimanual examination, which finding strongly suggests a mass is of uterine origin?

a) The mass is hard and nodular.

b) The mass is mobile from side to side only.

c) Movement of the cervix is transmitted to the abdominal mass.

d) The lower pole of the mass cannot be palpated.

Correct Answer: c
Leiomyoma cells have a higher concentration of which enzyme, leading to increased local estrogen levels?

a) Lipase

b) Amylase

c) Aromatase

d) Lactate dehydrogenase

Correct Answer: c

MOTIVATIONAL MESSAGE FROM DR. R. K. MISHRA:

The mastery of surgery is not found in the speed of your hands, but in the deliberate calm of a well-prepared mind. Cultivate discipline in study, for it is the only force that can forge knowledge into life-saving skill.

I wish you all continued focus and fulfillment as you advance in this demanding and profoundly rewarding profession.