Urgent — same day vet contact
Within 1 week
Skin mass that's growing or changing on a dog
Any rapidly growing, ulcerating, or changing skin lump needs prompt vet review with fine-needle aspirate or biopsy — early diagnosis matters.
Recognise the signs
- Lump growing rapidly
- Lump changing in size from day to day (classic mast cell tumour)
- Ulceration, bleeding, foul smell
- Lump that's firm, fixed, or invasive
First aid steps
- Photograph and measure with date.
- Phone the vet for prompt appointment.
- Fit a buster collar if the dog is licking or chewing the lump.
Do NOT
- Do not delay — early diagnosis often allows curative surgery.
- Do not squeeze or apply creams.
- Do not rely on appearance alone — fine-needle aspirate is essential.
When to phone the vet immediately
- Rapid growth
- Ulceration, bleeding, smell
- Dog unwell systemically
Common causes
- Mast cell tumour (variable in appearance)
- Soft tissue sarcoma
- Other tumours
- Histiocytoma (young dogs, often regresses spontaneously)
- Reactive lump (insect, infection)
What the vet will need to know
- When first noticed
- Growth rate
- Photo timeline
- Other lumps
Aftercare
- Fine-needle aspirate, biopsy, or excision and biopsy.
- Surgery, sometimes with radiotherapy or chemotherapy depending on type.
- Regular monitoring for recurrence or new masses.
Prevention
- Regular grooming with hands-on body checks.
- Annual exams catch many lumps early.
Breed-specific notes
- Mast cell tumour: Boxer, Bulldog, Boston Terrier, Pug, Labrador, Golden Retriever.
Frequently asked questions
Could a fast-growing lump be benign?
Possibly — abscesses and inflammatory lumps grow fast too. Aspirate distinguishes.
Should I just have any lump removed?
Aspirate first to characterise. Some lumps need wide-margin removal; others can be safely monitored.
Will my dog need chemotherapy?
Depends on tumour type, grade, and stage. Many cancers in dogs respond well to surgery alone or with adjunctive therapy.