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Health condition · Clinically reviewed

Liposarcoma, the most common soft tissue sarcoma in adults - explained.

Not every fatty lump is a lipoma. When a mass is large, deep or growing, specialist imaging, biopsy and sarcoma-centre care make the difference.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE and ESMO sarcoma guidance and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK sarcoma-centre pathways, MDM2 testing and specialist-commissioned treatment routes.

Key facts

Liposarcoma at a glance.

The essentials, in plain English - what it is, the subtypes, and how it’s diagnosed and treated in the UK today.

  • What it is

    A malignant tumour of adipocyte origin - the most common soft tissue sarcoma diagnosed in adults.

  • Main subtypes

    Well-differentiated, dedifferentiated, myxoid and pleomorphic - each behaving and responding differently.

  • Where it grows

    Retroperitoneum and the thigh are the classic sites; it is rare in other locations.

  • How it presents

    A painless, slowly enlarging mass - often already large by the time it is found, especially deep in the abdomen.

  • Diagnosis

    MRI for limb disease, CT for retroperitoneal staging, and a core needle biopsy before any treatment decision.

  • Treatment backbone

    Wide surgical resection at a specialist sarcoma centre, with radiotherapy and chemotherapy used selectively by subtype.

Why this guide matters

A rare cancer that hides behind a common lump.

Liposarcoma is easy to mistake for a lipoma and easy to under-investigate. The three points below shape everything else on this page.

  • Subtype changes everything

    Well-differentiated disease behaves quite differently to dedifferentiated, myxoid or pleomorphic liposarcoma - the plan follows the biology.

  • Biopsy comes before treatment

    A core needle biopsy at a specialist centre is mandatory before any surgery is planned - never excise a suspicious lump outside a sarcoma unit.

  • Centre choice affects outcome

    Surgery and MDT review at a specialist-commissioned sarcoma centre - Royal Marsden, Royal Orthopaedic, Birmingham and similar units - measurably improves results.

How the diagnosis is made

From a suspicious lump to a confirmed plan.

The steps a UK sarcoma centre will normally follow, per NICE and ESMO guidance - so you know what to expect and why.

  1. 01

    Assessing

    History and red-flag review

    A mass over 5cm, sited deep to fascia, growing rapidly or recurring after removal is treated as sarcoma until proven otherwise.

  2. 02

    Assessing

    Distinguishing from lipoma

    Benign lipomas are small, soft, mobile and superficial. Liposarcoma is more often large, deep, fixed and firm - see our lipoma guide for the contrast.

  3. 03

    Confirming

    MRI for extremity disease

    MRI is the gold-standard imaging test for a limb or trunk mass, defining size, depth and relationship to nerves and vessels.

  4. 04

    Confirming

    CT chest, abdomen and pelvis

    Retroperitoneal tumours need CT for local staging and to check for chest or peritoneal spread, arranged through a specialist-commissioned sarcoma pathway.

  5. 05

    Confirming

    Core needle biopsy

    Mandatory before any treatment decision. Read at a specialist sarcoma pathology centre, ideally with MDM2 FISH testing to confirm the diagnosis and grade.

  6. 06

    Planning

    Molecular profiling

    MDM2 amplification, FUS-DDIT3 fusion testing for myxoid disease and wider tumour molecular profiling refine subtype and treatment planning.

  7. 07

    Planning

    Sarcoma MDT review

    Every case is discussed at a specialist-commissioned sarcoma multidisciplinary team - centres such as the Royal Marsden, the Royal Orthopaedic Hospital and Birmingham lead UK care.

Typical timeline: imaging and biopsy within weeks, MDT-agreed plan shortly after.

Symptoms

What liposarcoma actually looks like.

Often a quietly enlarging mass with few other symptoms - and the features that mean it’s time to escalate.

  • Painless enlarging mass

    The most common presentation - a lump that grows slowly over months and rarely hurts until it is already substantial.

  • Abdominal fullness

    Retroperitoneal tumours can reach a large size before causing symptoms, presenting as vague fullness or early satiety.

  • Abdominal or flank pain

    Pain develops once a retroperitoneal mass presses on nerves, bowel or the kidney - often a later feature.

  • Unexplained weight loss

    A systemic feature of larger or higher-grade disease that should prompt urgent specialist assessment.

  • Deep limb swelling

    Extremity liposarcoma, particularly in the thigh, often presents as a deep swelling rather than a visible skin change.

  • A fixed, firm lump

    Unlike a lipoma, a liposarcoma tends to feel firm and does not move freely under the skin.

  • Recurrence after removal

    A lump that regrows after previous excision is a significant red flag and needs specialist sarcoma review.

  • Red flag - size and depth

    Any mass over 5cm, deep to fascia, growing quickly or recurrent warrants urgent MRI and a sarcoma referral.

WHO subtypes

Five subtypes, five different outlooks.

The World Health Organization classification drives grading, treatment intensity and follow-up.

  • Well-differentiated

    Also called atypical lipomatous tumour. Low grade, driven by MDM2 gene amplification, and the most indolent subtype.

  • Dedifferentiated

    Contains a higher-grade component alongside well-differentiated tissue - behaves more aggressively and needs closer follow-up.

  • Myxoid

    Defined by the t(12;16) FUS-DDIT3 gene fusion. Tends to affect younger patients and the limbs, and is notably chemosensitive.

  • Pleomorphic

    High grade and aggressive, with a greater tendency to metastasise - treated intensively from diagnosis.

  • Retroperitoneal liposarcoma

    Often reaches a large size before diagnosis. Managed at specialist-commissioned centres given the complexity of surgery involved.

Treatment

How liposarcoma is treated in the UK.

Surgery first, radiotherapy and chemotherapy layered in by subtype and site - all coordinated through a specialist sarcoma MDT.

  • Wide surgical resection

    The mainstay of treatment for all subtypes - performed at a specialist-commissioned sarcoma surgery centre with wide margins to reduce local recurrence.

  • Limb-sparing surgery

    For extremity disease, surgeons aim to preserve function wherever oncologically safe, reserving amputation for advanced or recurrent cases.

  • Radiotherapy

    Neoadjuvant or adjuvant radiotherapy is used for high-grade extremity disease to reduce local recurrence, delivered through specialist-commissioned services.

  • Chemotherapy

    Doxorubicin and ifosfamide are the standard combination; myxoid liposarcoma is notably more chemosensitive than other subtypes.

  • Trabectedin

    A myxoid-specific agent with particular activity against the FUS-DDIT3 fusion driving this subtype, used in specialist-commissioned oncology clinics.

  • Retroperitoneal multi-visceral surgery

    Retroperitoneal disease often requires complex resection involving adjacent organs, planned and delivered by a specialist sarcoma surgical team.

  • Pazopanib and targeted therapy

    An option for selected relapsed or metastatic soft tissue sarcoma, delivered through a specialist-commissioned pazopanib sarcoma clinic.

  • Long-term surveillance imaging

    Retroperitoneal liposarcoma can recur many years after treatment, so follow-up imaging continues well beyond the standard five-year window.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or sarcoma specialist knows your history and imaging and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Improving outcomes for people with sarcoma (CSG9) and NG applicable guidance.

  • ESMO Clinical Practice Guidelines. Soft tissue and visceral sarcomas: diagnosis, treatment and follow-up.

  • Royal Marsden and Royal Orthopaedic Hospital sarcoma service clinical guidance.

  • Sarcoma UK. Patient information on liposarcoma and soft tissue sarcoma pathways.

Red flags

When a lump needs urgent attention.

Most fatty lumps are lipomas. These are the features that shouldn’t be assumed benign without imaging.

  • Mass over 5cm

    Size alone is one of the strongest predictors of malignancy in a soft tissue lump and merits urgent imaging.

  • Deep to fascia

    A lump sited beneath the deep fascia rather than just under the skin carries a materially higher risk of sarcoma.

  • Rapid growth

    Any lump that visibly enlarges over weeks to months, rather than years, needs urgent specialist review.

  • Fixed and firm

    A mass that does not move freely and feels firm rather than soft is a recognised warning sign.

  • Recurrence after excision

    Regrowth of a previously removed lump strongly suggests incomplete excision of a malignant tumour.

  • Retroperitoneal mass with pain or weight loss

    Large abdominal masses with systemic symptoms should be referred urgently to a specialist sarcoma centre for staging.

  • Neurovascular symptoms in a limb

    Numbness, weakness or swelling from nerve or vessel compression by a limb mass needs urgent assessment.

  • Delayed biopsy or unplanned excision

    A suspected sarcoma should never be excised outside a specialist centre before imaging and biopsy - this can seed the surgical field and worsen outcomes.

  • New symptoms after previous treatment

    Retroperitoneal liposarcoma can recur years later, so new abdominal symptoms after treatment always warrant re-investigation.

Living with it

A treatable cancer, with the right team behind it.

Four things that make the biggest difference - the right centre, careful record-keeping, committed follow-up and specialist support.

A quiet reminder

Rare cancers deserve specialist centres.

It is reasonable, and often life-changing, to ask for referral to a named sarcoma centre if you have not already been offered one.

  1. 01 Referral

    Insist on a sarcoma centre

    Outcomes are consistently better when surgery and biopsy happen at a specialist-commissioned sarcoma unit, not a general surgical clinic.

  2. 02 Imaging

    Keep every scan

    MRI and CT reports and images travel with you between appointments and are invaluable if you seek a second opinion.

  3. 03 Follow-up

    Commit to long-term surveillance

    Retroperitoneal disease can return many years on - regular imaging follow-up is not optional, even when you feel completely well.

  4. 04 Support

    Use specialist charities

    Sarcoma UK and sarcoma-centre clinical nurse specialists offer practical and emotional support that general cancer services may not.

Frequently asked

Everything we get asked about liposarcoma.

Quick answers on subtypes, diagnosis, surgery and long-term follow-up.

  • What is liposarcoma?

    Liposarcoma is a malignant tumour arising from fat cells (adipocytes). It is the most common type of soft tissue sarcoma in adults and is classified by the World Health Organization into well-differentiated, dedifferentiated, myxoid and pleomorphic subtypes, each with a different growth pattern and outlook.

  • How is liposarcoma different from a lipoma?

    A lipoma is a benign fatty lump - usually small, soft, mobile and just under the skin. Liposarcoma is more likely to be large (over 5cm), deep to the fascia, firm, fixed and growing steadily. Any lump with these features should be assessed with MRI rather than assumed to be a lipoma.

  • What imaging is used to diagnose it?

    MRI is the gold-standard scan for a suspected limb or trunk liposarcoma, showing size, depth and involvement of nearby structures. Retroperitoneal (abdominal) tumours are staged with CT of the chest, abdomen and pelvis. A core needle biopsy at a specialist centre confirms the diagnosis before any treatment is planned.

  • Why does the subtype matter so much?

    Well-differentiated disease behaves in a low-grade, slow-growing way, often driven by MDM2 gene amplification. Dedifferentiated and pleomorphic subtypes are higher grade and more aggressive. Myxoid liposarcoma carries a specific FUS-DDIT3 gene fusion, tends to affect younger patients and the limbs, and responds notably well to chemotherapy, including trabectedin.

  • What does treatment usually involve?

    Wide surgical resection at a specialist sarcoma centre is the mainstay for every subtype. Radiotherapy is often added for high-grade extremity disease, and chemotherapy - particularly doxorubicin and ifosfamide, or trabectedin for myxoid tumours - is used where the disease is more chemosensitive or has spread. Retroperitoneal tumours frequently need complex, multi-organ surgery.

  • Can liposarcoma come back after treatment?

    Yes, and retroperitoneal disease in particular can recur many years after apparently successful surgery. This is why long-term surveillance imaging continues well beyond the timelines used for many other cancers, and why ongoing specialist sarcoma follow-up matters even after you feel fully recovered.

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