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PubMed This is a summary of 14 peer-reviewed journal articles Updated

Understanding Your Lipoma Diagnosis

At a Glance

A lipoma is a slow-growing, benign lump made of mature fat cells, usually found under the skin. Conventional lipomas do not turn into cancer or spread, but a clinician may recommend imaging, biopsy, or monitoring when a lump is unusual, painful, or changing.

Hearing the word tumor can be a frightening experience. In a medical context, however, a tumor simply refers to an abnormal growth of cells that forms a lump. When that tumor is a lipoma, it means the growth is benign (non-cancerous) [1]. Lipomas are the most common benign soft-tissue tumors found in adults, often making up nearly half of all non-cancerous soft-tissue growths [2][3].

What is a Lipoma?

A lipoma is a slow-growing mass made of mature adipocytes—the same type of fat cells found throughout your body [1]. While the exact cause is usually unknown, these cells continue to grow slowly in a localized area, clustering together into a soft, rubbery lump [4].

Researchers have found that some lipomas contain localized somatic genetic alterations. For example, a gene called HMGA2 can become rearranged, which contributes to the fat cells continuing to proliferate [5]. These molecular findings are mainly tools for specialists to understand how the lump grows; they are not caused by your weight or diet.

Why It Is Not Cancer

It is a common and valid fear to worry that a lipoma might “turn into” cancer over time. However, medical evidence shows that standard, conventional lipomas are fundamentally different from liposarcomas (cancerous fat tumors) [1][6].

  • Fixed Biology: A lipoma starts as a benign growth and stays that way. Standard lipomas do not transform into cancer [7][8].
  • Distinct Molecular Markers: Doctors can tell the difference between a lipoma and a rare cancerous growth by looking for specific genetic markers. For example, a protein called MDM2 is amplified in many cancerous fat tumors but is normal in benign lipomas [6][9].
  • Different Growth Patterns: While lipomas can grow slowly over many years, they do not invade nearby tissues or spread to other parts of the body (metastasize) [1].

Who Gets Lipomas?

Lipomas are very common, though because they are often painless and harmless, many people never even report them to a doctor [10]. They are most frequently diagnosed in adults between the ages of 40 and 60, though they can appear at any time [11][12].

Most people have only one lipoma, but it is not unusual to develop several over a lifetime. While they can appear anywhere fat cells exist, they are most often found just under the skin on the shoulders, neck, trunk, and arms. In the vast majority of cases, these lumps are “incidental findings”—meaning they are discovered during a routine exam or while looking for something else—and require no treatment unless they become painful or bothersome [13][14].

Common questions in this guide

What exactly is a lipoma?
A lipoma is a slow-growing, noncancerous lump made of mature fat cells. It usually feels soft or rubbery and sits just under the skin, often on the shoulders, neck, trunk, or arms.
Can a conventional lipoma become cancerous?
No. A conventional lipoma does not transform into cancer or spread to other parts of the body. Liposarcoma is a separate, rare cancerous fat tumor, so a changing or unusual lump should still be assessed by a clinician.
How can doctors tell a lipoma from liposarcoma?
Doctors consider the lump’s growth pattern, feel, location, and other clinical features. If needed, imaging or a biopsy can provide more information; MDM2 amplification is common in many liposarcomas but is generally normal in benign lipomas.
Does every lipoma need treatment?
Many lipomas need no treatment if they are painless and not bothersome. A clinician may recommend observation and ask you to watch for changes, while pain, discomfort, or restricted movement may prompt a discussion of next steps.
When might a lipoma need imaging or a biopsy?
Imaging or a biopsy may be considered when the diagnosis is uncertain or the lump changes in size, texture, or sensation. Your clinician can determine whether monitoring is appropriate based on the lump’s location and features.
What causes a lipoma?
The exact cause of most lipomas is unknown, and they are not caused by body weight or diet. Some lipomas contain a localized HMGA2 gene rearrangement, which may help explain their growth but is not something a person causes.

Related questions

Can an Injury or Bump Cause a Lipoma to Form? What to Know Can Weight Loss, Diet, or Exercise Shrink a Lipoma? How Common Are Lipomas in Adults, and Should I Worry?

Get notified when new evidence is published on lipoma.

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References

References (14)
  1. 1

    Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma of the Salivary Gland and Its Diagnostic Challenges: A Case Report and Literature Review.

    Khan B, Khan J, Al Hmada Y, Abbas S

    International journal of surgical pathology 2026; 10668969261458405 doi:10.1177/10668969261458405.

    PMID: 42484517
  2. 2

    Giant lipoma of the hand causing median nerve compression.

    Clesham K, Galbraith JG, Ramasamy A, Karkuri A

    BMJ case reports 2017; (2017()) doi:10.1136/bcr-2017-220056.

    PMID: 28659368
  3. 3

    Epidemiology of musculoskeletal tumors in a reference unit.

    Huguet-Carmona JL, De la Calva-Ceinos C, González-Rojo P, et al.

    Revista espanola de cirugia ortopedica y traumatologia 2025; (69(2)):158-166 doi:10.1016/j.recot.2024.07.012.

    PMID: 39025360
  4. 4

    Reduced lipolysis in lipoma phenocopies lipid accumulation in obesity.

    Le Duc D, Lin CC, Popkova Y, et al.

    International journal of obesity (2005) 2021; (45(3)):565-576 doi:10.1038/s41366-020-00716-y.

    PMID: 33235355
  5. 5

    Fusion of the High-mobility Group AT-Hook 2 (HMGA2) and the Gelsolin (GSN) Genes in Lipomas With t(9;12)(q33;q14) Chromosomal Translocation.

    Panagopoulos I, Andersen K, Brunetti M, et al.

    In vivo (Athens, Greece) 2023; (37(2)):524-530 doi:10.21873/invivo.13110.

    PMID: 36881074
  6. 6

    Well-differentiated liposarcoma and dedifferentiated liposarcoma: An updated review.

    Thway K

    Seminars in diagnostic pathology 2019; (36(2)):112-121 doi:10.1053/j.semdp.2019.02.006.

    PMID: 30852045
  7. 7

    Laparoscopic management of a gastric liposarcoma with malignant transformation from a gastric lipoma: A rare case report.

    Choi K

    International journal of surgery case reports 2023; (113()):109039 doi:10.1016/j.ijscr.2023.109039.

    PMID: 37992666
  8. 8

    Aggressive Orbital Dedifferentiated Liposarcoma With Osseus Components in a Young Woman.

    Kase S, Maeda T, Otsuka N, et al.

    Cancer diagnosis & prognosis 2025; (5(3)):404-409 doi:10.21873/cdp.10453.

    PMID: 40322209
  9. 9

    MDM2 RNA In Situ Hybridization for the Diagnosis of Atypical Lipomatous Tumor: A Study Evaluating DNA, RNA, and Protein Expression.

    Kulkarni AS, Wojcik JB, Chougule A, et al.

    The American journal of surgical pathology 2019; (43(4)):446-454 doi:10.1097/PAS.0000000000001199.

    PMID: 30520819
  10. 10

    Large airway-obstructing retropharyngeal lipoma in an asymptomatic patient: a case report.

    Ehlers SA, Bozanich JM, Arashlow MT, et al.

    International journal of implant dentistry 2020; (6(1)):38 doi:10.1186/s40729-020-00237-3.

    PMID: 32803431
  11. 11

    Oral lipoma: Case report and review of literature.

    Dehghani N, Razmara F, Padeganeh T, Mahmoudi X

    Clinical case reports 2019; (7(4)):809-815 doi:10.1002/ccr3.2099.

    PMID: 30997091
  12. 12

    Intraoral lipomas: Review of literature and report of two clinical cases.

    Egido-Moreno S, Lozano-Porras AB, Mishra S, et al.

    Journal of clinical and experimental dentistry 2016; (8(5)):e597-e603 doi:10.4317/jced.52926.

    PMID: 27957277
  13. 13

    Large lipoma of the ascending colon: a case report and review of literature.

    Farfour AN, AbuOmar NA, Alsohaibani FI

    Journal of surgical case reports 2020; (2020(9)):rjaa354 doi:10.1093/jscr/rjaa354.

    PMID: 32968480
  14. 14

    Giant lipoma of the colon presenting as a case of adult intussusception: A case series.

    Nureta TH, Girma T, Muleta LE, et al.

    International journal of surgery case reports 2023; (106()):108279 doi:10.1016/j.ijscr.2023.108279.

    PMID: 37148723

This page explains lipoma diagnosis for informational purposes only and does not constitute medical advice. A clinician should evaluate any new, changing, painful, or uncertain lump and advise whether imaging, biopsy, or monitoring is appropriate.

Guide contents lipoma
Research & Literature
02 Symptoms, Variants, and Related Syndromes