Can malignant fibrous histiocytoma spread to other animals?

No, it is not contagious. This type of tumour arises from abnormal cell changes within the individual and cannot be transmitted to other animals. If there is an open wound, avoid direct contact and consult your vet.

What should I do if I find a lump under my pet's skin or in the abdomen?

Take photos and note any changes in size, then bring your pet to the vet as soon as possible. The vet may arrange blood tests, imaging, or a biopsy to identify the cause.

What treatment options are available, and how effective are they?

Treatment may include surgical excision, radiation, or drug therapy. Outcomes vary depending on tumour size, location, and whether metastasis has occurred; your vet will assess each case individually.

How soon after discovery does timing affect the prognosis?

Prognosis depends on early detection and the possibility of complete excision. The earlier the tumour is assessed and treated, the better the chances of successful management. Ask your vet for an individual case assessment.

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

Malignant Fibrous Histiocytoma in Dogs & Cats: Symptoms, Diagnosis & Treatment Guide [2025]

Malignant fibrous histiocytoma is an aggressive soft tissue tumour. Wide surgical excision is the primary treatment, often combined with chemotherapy or radiation therapy.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: AVMA, ACVIM, National Taiwan University Veterinary Hospital

When to See a Vet

Requires immediate veterinary care (emergency)

•Complete refusal to eat for more than a full day with poor spirits
•Mass rapidly enlarging or ulcerating on the surface with continuous bleeding
•Rapid breathing or inability to lie flat with marked exhaustion

Recommend scheduling a clinic visit soon (within 24-72 hours)

•Markedly reduced appetite for more than three days with weight loss
•Reduced activity, unwilling to play, and ongoing changes
•A palpable subcutaneous or abdominal mass that is gradually enlarging

01What Symptoms Indicate a Problem?

Malignant fibrous histiocytoma in dogs and cats often presents with non-specific systemic signs or a localised lump, requiring further imaging and pathology to confirm the diagnosis.

Changes in demeanour, obvious lethargy, or decreased activity levels
Reduced appetite, picky eating, or a significant drop in food intake
Gradual weight loss over a short period, leading to noticeable thinning
Reluctance to run, jump, or play; tires more easily than usual
A palpable mass under the skin or in the abdomen, with changes in size or shape
Symptoms lasting more than two weeks or any change in the mass should prompt a specialist assessment

02How to Assess Abnormalities at Home: Observation Tips and When to Seek Emergency Care

Systematic home monitoring helps your vet understand the disease progression and arrange appropriate tests — keep detailed records to share at your appointment.

Record changes in energy and activity each day (e.g. whether your pet is willing to get up)
Weigh your pet daily and note the figures, including the date and time of each measurement
Track daily food intake and meal frequency; note any pickiness or refusal to eat
Monitor toileting frequency and the appearance of urine and faeces (any blood or unusual odour)
Take photos or short videos of the lump with your phone to share with your vet
If symptoms worsen or persist, arrange a clinic visit as soon as possible

03How Will the Vet Diagnose the Condition? Common Diagnostic Tests

At the clinic, the vet will use blood tests, imaging, and pathology to assess your pet's overall condition, tumour location, and staging, in order to develop an individualised treatment plan.

Complete blood count (CBC)

checks for anaemia, infection, or inflammation markers

Blood biochemistry panel

evaluates liver and kidney function and overall metabolic status

Urinalysis

assesses kidney function and rules out urinary tract infection

X-rays

examines the chest and abdomen for metastasis or associated changes

Biopsy or fine-needle aspirate (FNA)

confirms the pathological type and degree of malignancy

Advanced imaging (CT or MRI)

determines tumour extent and local invasion

Referral to a specialist hospital with advanced imaging and pathology capabilities is recommended

04How to Treat and Care for Your Pet After Diagnosis: Medication, Diet, and Care Guide

Treatment and follow-up must be tailored to the pathology report and your pet's overall condition; blood monitoring and imaging follow-up during and after treatment are essential to assess response.

Treatment options may include surgical excision, radiation therapy, or systemic drug therapy
Regular check-ups and blood tests are required during chemotherapy or other drug treatments
Imaging follow-up is scheduled post-surgery or during treatment to assess tumour response and detect recurrence
Dietary adjustments and home care can improve quality of life and treatment tolerance
If symptoms change or worsen, return to the clinic early or seek specialist assistance

05What to Prepare Before the Vet Visit: Key Information to Help Your Vet Quickly Assess the Cause

Note when symptoms first appeared, how they have changed, and any significant events

Prepare daily records of food intake, weight, and toileting for your vet

List all current medications, supplements, and any known allergies or sensitivities

Bring recent photos or videos and any previous examination reports if available

Consider booking a specialist appointment or ask the clinic to arrange imaging in advance

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.