Can sarcomas spread to other parts of the body?

Certain sarcoma types carry a risk of metastasis. Whether metastasis has occurred requires imaging (such as X-rays or CT) and further tests — your vet can advise on an appropriate staging workup.

How can I tell if a lump is benign or malignant?

A definitive answer requires fine-needle aspiration cytology or a tissue biopsy combined with imaging. Follow your vet's recommendation to arrange the appropriate tests.

Is a biopsy painful or risky?

Biopsies are typically performed under local anaesthesia or brief sedation. Your vet will assess the risks and explain what to watch for afterwards; wound monitoring is required post-procedure.

How often should I bring my pet back for follow-up after a lump is found?

Follow-up frequency depends on the tumor type and treatment plan. Regular imaging and blood tests are generally recommended after surgery, chemotherapy, or conservative monitoring — follow your vet's schedule.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Sarcoma in Dogs & Cats: Symptoms, Imaging & Treatment [2025]

Osteosarcoma is the most common malignant bone tumor in dogs, frequently occurring in the limb bones of large breeds. Amputation combined with chemotherapy can extend survival time.

Take 1 minute to check the symptoms first

Last updated: 2026/01/06

Pethealthmap Editorial Team

Sources: AVMA, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate emergency care

•The lump suddenly swells rapidly with heavy bleeding
•The lump has ruptured and the wound continues to bleed uncontrollably
•Sudden inability to walk normally or a significant worsening of lameness

Schedule a clinic visit soon (within 24–72 hours)

•Recurring limping or shifting of weight on one limb, but the pet can still walk briefly
•Obvious pain response or avoidance when the lump is touched
•Decreased appetite and gradual weight loss, but still alert

01What symptoms signal a problem?

Sarcomas typically present first as a localized lump; pain from the mass or surrounding tissue leads to limping or reduced activity.

A localized lump you can feel, or an existing lump that is gradually growing
Recurring lameness or a noticeable shift in how your pet bears weight on one side
Pain or avoidance response when the area is touched or pressed
Reduced activity, reluctance to jump, or fewer walks
Decreased appetite or gradual weight loss
Schedule an oncology or imaging assessment as soon as possible

Seek emergency care immediately if you notice the following symptoms:

⚠️ A lump that rapidly swells and bleeds heavily
⚠️ A ruptured lump with continuous bleeding that will not stop
⚠️ Sudden inability to walk normally or a dramatic worsening of lameness

02How to monitor at home? Key observations and criteria for emergency care

Systematically recording symptoms and changes at home helps your vet make a faster assessment and arrange appropriate tests.

Note the date and time when you first noticed the lump or abnormality
Take close-up photos of the lump and videos of your pet walking from the front and side
Record daily appetite, water intake, urination, and defecation
Watch whether the lump becomes harder, redder, or develops discharge or bleeding
Weigh your pet daily and track any weight trend
If you notice significant pain or heavy bleeding, call your clinic for advice first

03How will the vet make a diagnosis? Common diagnostic tests

Your vet will combine a physical examination with imaging and laboratory tests to assess the extent of the tumor, its likely type, and your pet's overall health.

Physical exam

palpation of the lump, evaluation of pain and local tissue invasion

X-rays

to assess bone involvement and check for metastases in the chest or abdomen

CT / MRI

to evaluate tumor depth and its relationship to surrounding structures

Fine-needle aspiration cytology or tissue biopsy to confirm the tumor type

Blood chemistry panel and urinalysis to assess organ function and surgical risk

04What treatment and care come after diagnosis? Medication, diet & care guide

Sarcoma treatment often requires surgical excision and/or additional oncological therapy; regular follow-up after surgery is essential to monitor for recurrence or metastasis.

Surgery: extent of excision and reconstruction depends on location and tumor size
Chemotherapy or radiation therapy as adjuvant or alternative depending on tumor type and stage
Pain management and supportive medications to improve quality of life and appetite
Nutritional management and weight maintenance to support post-operative recovery
Regular follow-up visits for imaging, blood chemistry, and clinical monitoring
Multidisciplinary specialist consultation when needed for long-term management planning

05What to prepare before your vet visit? Key information to help your vet identify the problem quickly

Bring photos of the lump and videos of your pet walking from the front and side

Prepare a written record of when symptoms started and how they have changed

Note any recent changes in appetite, elimination habits, and activity level

List all current medications and supplements your pet is taking

Bring any previous diagnostic reports or images if available

Call ahead to book an appointment and let the clinic know a biopsy or advanced imaging may be needed

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Lameness

Limping

Edema

Tissue swelling

Tumor

Neoplasm