Lipoma: Symptoms, Causes & Removal Options

What Is a Lipoma?

A lipoma is a benign (non-cancerous) tumor composed of mature fat cells that forms a soft, movable lump under the skin. Lipomas are the most common type of soft tissue tumor, affecting approximately 1% of the general population. They grow slowly over months to years and are harmless, though they can sometimes cause cosmetic concerns or discomfort.

Lipomas develop when fat cells multiply and clump together within a thin, fibrous capsule just beneath the skin's surface. This capsule is what gives lipomas their characteristic smooth, rounded shape and allows them to move easily when pressed. Unlike normal fat tissue that can shrink with weight loss, lipomas maintain their structure independently of changes in body weight.

The term "lipoma" comes from the Greek words "lipos" (fat) and "oma" (tumor), literally meaning "fat tumor." While the word "tumor" might sound alarming, it simply refers to an abnormal growth of tissue—in this case, completely harmless fat cells. Medical professionals classify lipomas as benign neoplasms, meaning they do not invade surrounding tissues, do not spread to other parts of the body, and have an extremely low risk of becoming cancerous.

Lipomas can occur anywhere on the body where fat tissue exists, but they most commonly develop on the trunk (particularly the upper back and shoulders), upper arms, thighs, and neck. They rarely form on the face, hands, feet, or lower legs. In some cases, lipomas can develop in deeper tissues, including muscles, nerves, and even internal organs, though these deep lipomas are less common than subcutaneous (under-the-skin) varieties.

Types of Lipomas

While most lipomas are classified as conventional subcutaneous lipomas, several distinct subtypes exist based on their location, composition, and clinical characteristics. Understanding these variations helps physicians accurately diagnose and manage different presentations.

• Subcutaneous lipoma: The most common type, located just beneath the skin surface
• Angiolipoma: Contains blood vessels along with fat tissue, often tender or painful
• Fibrolipoma: Has a higher proportion of fibrous tissue, making it firmer than typical lipomas
• Spindle cell lipoma: Contains distinctive spindle-shaped cells, usually found on the neck and upper back
• Pleomorphic lipoma: Contains cells of varying shapes and sizes, typically found in older men
• Intramuscular lipoma: Develops within muscle tissue rather than under the skin
• Hibernoma: Made of brown fat cells rather than white fat, rare and typically benign

How Common Are Lipomas?

Lipomas are remarkably common, representing the most frequently diagnosed soft tissue tumor in adults. Population studies estimate that approximately 1% of people will develop at least one lipoma during their lifetime, though the actual prevalence may be higher since many small lipomas go unnoticed or unreported.

These fatty lumps can occur at any age but are most commonly diagnosed in adults between 40 and 60 years old. They appear with roughly equal frequency in men and women, though some subtypes show gender preferences. Lipomas can develop as single growths or, in some cases, people may develop multiple lipomas—a condition sometimes called familial multiple lipomatosis when it runs in families.

What Are the Symptoms of a Lipoma?

A lipoma typically presents as a soft, rubbery lump under the skin that moves easily when pressed. Most lipomas are painless and range from 1 to 5 centimeters in diameter. The characteristic feel is often described as "doughy" or like a small ball of soft rubber beneath the skin's surface.

Recognizing a lipoma involves understanding its distinctive physical characteristics. When you feel a lipoma, you'll notice it has a unique texture and behavior that sets it apart from other types of lumps. The consistency is typically soft and pliable, similar to a small blob of dough under the skin. Unlike fluid-filled cysts, which may feel slightly fluctuant, or muscle knots, which feel firm, lipomas have a distinctive rubbery quality that physicians learn to recognize through experience.

One of the most helpful diagnostic features of a lipoma is its mobility. Because the fatty tumor is encapsulated and sits in the subcutaneous tissue layer, it typically slides freely under the skin when you push on it. This mobility, combined with the soft texture, helps distinguish lipomas from more concerning lumps that might be fixed to underlying structures or feel hard and irregular.

Physical Characteristics

Understanding the typical physical features of lipomas can help you identify them and know when to seek medical evaluation. While variations exist, most lipomas share several common characteristics that physicians use for clinical diagnosis.

• Texture: Soft, rubbery, and doughy—easily compressed when pressed
• Shape: Rounded or oval with smooth, regular borders
• Mobility: Moves freely under the skin when pushed (not attached to underlying structures)
• Size: Usually 1-5 cm in diameter, though they can grow larger
• Growth rate: Very slow, typically developing over months to years
• Skin appearance: Normal skin color over the lump (no redness or skin changes)
• Pain: Usually painless, though some may be tender if pressing on nerves

Location Patterns

Lipomas show a preference for certain body regions, though they can technically develop anywhere fat tissue exists. The distribution pattern can help physicians anticipate likely diagnoses when evaluating soft tissue lumps.

The most common locations for lipomas include the upper back and shoulders, where they often go unnoticed for years until someone points them out or they're felt during a massage or examination. The upper arms, particularly the outer aspect, represent another frequent site. Thighs, both front and back, commonly harbor lipomas as well. The neck, especially the back of the neck, and the trunk (chest and abdomen) are also typical locations.

Interestingly, lipomas rarely develop on the face, hands, feet, or lower legs below the knee. When fatty lumps appear in these unusual locations, physicians may consider alternative diagnoses or perform additional evaluation to confirm the nature of the growth.

When Lipomas Cause Symptoms

While most lipomas remain completely asymptomatic throughout a person's life, some can cause noticeable symptoms depending on their size, location, and relationship to surrounding structures. Pain, discomfort, or functional problems occur in a minority of cases but warrant attention when present.

Pain associated with lipomas most commonly occurs when the growth presses against nearby nerves. These nerve-compressing lipomas may cause aching, shooting pain, or tingling in the affected area. Angiolipomas, the subtype containing blood vessels, are inherently more likely to be tender or painful even without nerve compression.

Larger lipomas, particularly those exceeding 5 centimeters, may cause cosmetic concerns or physical discomfort simply due to their size. They might be visible through clothing, interfere with movement if located near joints, or cause a sense of pressure in the affected area. Intramuscular lipomas can affect muscle function and may cause weakness or discomfort during physical activity.

What Causes Lipomas to Develop?

The exact cause of lipomas is not fully understood, but they appear to have a genetic component, as they often run in families. Lipomas form when fat cells within the subcutaneous tissue layer multiply and cluster together within a fibrous capsule. While minor injuries have been suggested as potential triggers, this connection remains unproven.

Despite being the most common soft tissue tumor, the precise mechanisms that cause lipomas to develop remain incompletely understood. Research has identified several factors that appear to play a role, but no single cause has been definitively established. This gap in knowledge reflects the generally benign nature of lipomas—because they rarely cause problems, they receive less research attention than more serious conditions.

What scientists do know is that lipomas consist of mature adipocytes (fat cells) that have multiplied beyond normal tissue requirements. These cells accumulate within a thin connective tissue capsule that separates them from surrounding normal fat. The capsule gives lipomas their characteristic smooth borders and contributes to their mobility under the skin.

Genetic Factors

Heredity appears to play the most significant role in lipoma development. Studies have shown that lipomas tend to cluster in families, with some individuals inheriting a predisposition to develop these fatty growths. When a person develops multiple lipomas, the likelihood of a genetic component increases substantially.

Certain genetic syndromes are associated with the development of multiple lipomas. Familial multiple lipomatosis, an inherited condition, causes affected individuals to develop numerous lipomas throughout their lifetime. Dercum's disease (adiposis dolorosa) involves the growth of multiple painful lipomas, typically in overweight women. Gardner syndrome and Madelung disease also feature lipomas as part of their clinical presentation.

Chromosomal abnormalities have been identified in some lipomas, particularly rearrangements involving chromosomes 12, 6, and 13. The most common genetic change involves the HMGA2 gene on chromosome 12, which codes for a protein involved in cell growth and differentiation. However, many lipomas show no detectable chromosomal abnormalities, suggesting that other genetic or epigenetic factors may be involved.

Other Potential Contributing Factors

Several other factors have been proposed to contribute to lipoma formation, though none have been definitively proven. Understanding these potential associations helps provide a complete picture of what might influence lipoma development.

• Minor trauma: Some researchers have suggested that minor injuries might trigger lipoma formation in susceptible individuals, though this "trauma theory" lacks strong scientific support
• Age: The peak incidence between ages 40-60 suggests age-related factors may contribute
• Metabolic factors: While obesity does not cause lipomas, existing lipomas may enlarge with weight gain
• Lipid metabolism: Some studies have explored connections to cholesterol and lipid levels, but results are inconclusive
• Medications: Certain drugs, particularly corticosteroids and protease inhibitors, have been associated with lipomatosis in rare cases

When Should You See a Doctor About a Lipoma?

See a doctor if your lipoma is growing rapidly, becoming painful, hardening, larger than 5 cm, or if you're uncertain whether the lump is a lipoma. While most lipomas are harmless, these changes may warrant evaluation to rule out other conditions. Any new lump that feels hard, immovable, or grows quickly should be examined promptly.

Most lipomas are discovered incidentally during routine physical examinations or self-inspection and require no medical intervention. However, certain situations warrant professional evaluation to ensure accurate diagnosis and appropriate management. Understanding these warning signs helps you make informed decisions about seeking medical care.

The primary reason to seek evaluation is uncertainty about diagnosis. While experienced physicians can often diagnose lipomas through physical examination alone, some lumps may have ambiguous features that make differentiation from other conditions difficult. In these cases, additional testing such as ultrasound, MRI, or biopsy may be needed to confirm the diagnosis and rule out more concerning possibilities.

Signs That Warrant Medical Evaluation

Certain characteristics or changes in a lipoma should prompt you to schedule an appointment with your healthcare provider. These features don't necessarily indicate a serious problem but deserve professional assessment.

• Rapid growth: Sudden increase in size over weeks rather than months
• Change in texture: Becoming harder, firmer, or irregular
• Pain development: New or worsening pain, especially without obvious cause
• Large size: Lumps larger than 5 cm (about 2 inches) in diameter
• Fixed position: Loss of mobility, feeling attached to deeper structures
• Skin changes: Redness, warmth, or changes in overlying skin
• Functional impact: Interference with movement or daily activities
• Cosmetic concerns: Visible lumps causing distress or self-consciousness

Distinguishing Lipomas from Other Lumps

Several other conditions can cause lumps under the skin that might be mistaken for lipomas. While only a medical professional can make a definitive diagnosis, understanding the differences can help you communicate concerns effectively and recognize when prompt evaluation is needed.

Cysts, particularly epidermoid cysts, are among the most common conditions confused with lipomas. Unlike lipomas, cysts typically have a small central punctum (opening), may have a slightly different texture, and can become inflamed or infected. Cysts contain keratin rather than fat and may occasionally drain a thick, cheesy material.

Liposarcomas are rare malignant tumors that can sometimes initially resemble lipomas. Warning signs that suggest possible liposarcoma rather than benign lipoma include rapid growth, large size (especially over 5 cm), deep location, firm or hard texture, and fixation to surrounding structures. These features warrant prompt medical evaluation and often require imaging studies and biopsy for definitive diagnosis.

How Are Lipomas Diagnosed?

Most lipomas are diagnosed through physical examination alone, based on their characteristic soft, rubbery texture and mobility under the skin. When the diagnosis is uncertain, ultrasound is typically the first imaging study performed. MRI provides detailed imaging for deep or large lipomas, and biopsy may be needed in rare cases to definitively rule out malignancy.

The diagnosis of a typical subcutaneous lipoma is often straightforward for experienced healthcare providers. The combination of characteristic physical findings—soft texture, smooth borders, mobility, slow growth, and lack of overlying skin changes—allows confident clinical diagnosis in most cases without the need for additional testing.

During physical examination, your doctor will assess the lump's size, shape, consistency, mobility, and relationship to surrounding structures. They'll ask about how long you've noticed it, whether it has changed, and whether you have any symptoms. A history of similar lumps or family history of lipomas adds supporting evidence for the diagnosis.

Imaging Studies

When physical examination alone cannot definitively establish the diagnosis, imaging studies help characterize the lump and guide management decisions. Different imaging modalities provide complementary information and are selected based on the clinical situation.

Ultrasound is typically the first imaging study ordered when additional information is needed. It's non-invasive, readily available, and relatively inexpensive. On ultrasound, lipomas appear as well-defined, oval masses that are isoechoic or slightly hyperechoic compared to surrounding fat. The examination can assess size, depth, and relationship to adjacent structures.

MRI (Magnetic Resonance Imaging) provides the most detailed characterization of soft tissue masses and is particularly useful for large lipomas, deep-seated lipomas, or when there's concern about possible malignancy. Lipomas have a characteristic appearance on MRI that closely matches normal fat tissue. MRI can also detect features that might suggest liposarcoma, such as thick septa, nodular components, or areas that don't follow fat signal.

CT (Computed Tomography) may be used in certain situations, particularly for evaluating lipomas in the abdomen or chest. Like MRI, CT can measure the density of the mass and confirm its fatty composition.

Biopsy

Biopsy—removing a tissue sample for microscopic examination—is rarely needed for typical lipomas but may be recommended in certain circumstances. The decision to biopsy depends on clinical features, imaging findings, and the level of diagnostic certainty.

Indications for biopsy include large tumors (especially those over 5-10 cm), deep location, rapid growth, atypical imaging features, or persistent diagnostic uncertainty. Biopsy can definitively distinguish lipoma from liposarcoma and identify specific lipoma subtypes that might influence management.

Biopsy techniques include fine needle aspiration (FNA), core needle biopsy, and excisional biopsy. Fine needle aspiration has limited accuracy for fatty tumors and is generally not recommended. Core needle biopsy provides more tissue and better diagnostic accuracy. In many cases, physicians opt for complete excisional biopsy, which serves both diagnostic and therapeutic purposes.

How Are Lipomas Treated?

Most lipomas don't require treatment unless they cause symptoms, cosmetic concerns, or diagnostic uncertainty. When removal is desired, surgical excision under local anesthesia is the standard approach, offering complete removal with minimal recovery time. Alternative options include liposuction for larger lipomas and steroid injections to reduce size, though these are less commonly used.

The management of lipomas follows a patient-centered approach that considers the individual's symptoms, concerns, and preferences alongside the clinical characteristics of the tumor. Because lipomas are benign and rarely cause problems, the decision to treat is often elective rather than medically necessary.

For many people with small, asymptomatic lipomas, observation is the appropriate choice. This "watchful waiting" approach involves monitoring the lipoma over time without active intervention. Patients are educated about what changes would warrant reevaluation, such as rapid growth, pain, or textural changes. Many lipomas remain stable for years or even decades and never require treatment.

Surgical Excision

When treatment is indicated, surgical excision remains the gold standard for lipoma removal. This procedure offers the advantage of complete removal with pathological confirmation of the diagnosis. Surgical excision is appropriate for lipomas of any size and is typically the preferred approach for symptomatic or cosmetically concerning growths.

The procedure is usually performed as an outpatient surgery under local anesthesia. After numbing the area, the surgeon makes an incision over the lipoma, identifies the capsule surrounding the fatty tumor, and carefully dissects it free from surrounding tissues. The entire encapsulated mass is removed, and the incision is closed with sutures. The procedure typically takes 15-45 minutes depending on the lipoma's size and location.

Recovery from lipoma excision is generally straightforward. Most patients experience mild discomfort, bruising, and swelling at the surgical site for several days. Over-the-counter pain medications usually provide adequate relief. Sutures are typically removed after 7-14 days, and most people can return to normal activities within a few days to a week. Strenuous activity may need to be avoided for 2-4 weeks depending on the surgery's extent and location.

Liposuction

Liposuction offers a minimally invasive alternative to traditional surgical excision, particularly for larger lipomas where a smaller scar is desired. This technique uses a thin cannula (tube) inserted through a small incision to suction out the fatty tissue comprising the lipoma.

The advantages of liposuction include smaller incisions, potentially faster recovery, and better cosmetic outcomes for larger lipomas. However, the technique has limitations. Because liposuction cannot remove the fibrous capsule that encases most lipomas, there's a higher risk of recurrence compared to complete surgical excision. Liposuction also doesn't provide a complete tissue sample for pathological examination, which may be a concern when diagnostic certainty is important.

Steroid Injections

Injection of corticosteroids directly into a lipoma can cause the fatty tissue to shrink, reducing the tumor's size without surgical removal. This approach may be considered for patients who prefer to avoid surgery or for lipomas in locations where surgery might be challenging.

Results with steroid injections are variable and typically modest—most lipomas shrink but don't disappear completely. Multiple injections may be needed to achieve noticeable reduction. This option is best suited for smaller lipomas where cosmetic improvement rather than complete removal is the goal.

Recurrence After Treatment

When a lipoma is completely removed through surgical excision, recurrence at the same site is uncommon, occurring in approximately 1-2% of cases. Recurrence is more likely if the capsule was not completely removed or if the lipoma was incompletely excised due to its size or location. Liposuction carries a higher recurrence rate because it cannot remove the capsule.

It's important to understand that having one lipoma increases the likelihood of developing additional lipomas in other locations over time. This is not recurrence but rather the development of new, separate growths—a pattern that may reflect underlying genetic predisposition.

Can You Prevent Lipomas?

There is no known way to prevent lipomas from developing. Because the exact cause of lipomas remains unclear and genetic factors appear to play a significant role, preventive measures are not available. However, maintaining overall health and monitoring existing lipomas for changes remains important.

Given our incomplete understanding of what causes lipomas, there are no evidence-based strategies for preventing their formation. Unlike some conditions where lifestyle modifications can reduce risk, lipomas appear to develop primarily due to genetic factors that cannot be modified through diet, exercise, or other interventions.

While weight management doesn't prevent lipoma formation, maintaining a healthy weight may help keep existing lipomas from growing larger. The fat cells within lipomas can expand with weight gain, potentially making previously unnoticeable lipomas more prominent or symptomatic. However, weight loss won't make existing lipomas disappear—the encapsulated fatty tissue remains even when body fat decreases.

Monitoring and Follow-Up

For individuals with known lipomas who have chosen observation rather than removal, periodic self-examination helps detect any changes that might warrant medical evaluation. Familiarity with your lipoma's baseline characteristics—size, texture, location—allows you to recognize meaningful changes.

Consider taking photographs of visible lipomas for comparison over time. Measure the lipoma periodically using a ruler to objectively track any size changes. Note any new symptoms such as pain or tenderness. Report significant changes to your healthcare provider, particularly rapid growth or changes in texture.

For those with a family history of multiple lipomas or who have already developed several lipomas, more attentive monitoring may be appropriate. While the condition itself is benign, staying aware of new growths and changes in existing ones ensures timely evaluation when needed.