Cat symptom
Lumps & masses in cats
A new bump or growth on or under the skin. Many lumps are harmless (like fatty lumps), but you can't tell benign from serious by feel alone — any new, changing, or fast-growing lump should be checked.
Common causes of lumps & masses in cats
- Benign fatty lumps (lipomas) or cysts
- Warts or insect-bite reactions
- Abscesses (infected swellings)
- Skin tumors, including some cancers
Who's most at risk
- Middle-aged and senior pets
- Breeds prone to skin tumors
- Outdoor pets (bites, abscesses)
- A history of skin masses
What you can do at home
- Note the size, location, and date you found it; watch for changes
- Take a photo and measure it so your vet can track growth
- Don't squeeze, pop, or apply home remedies
When to see a vet
- Any new lump — get it checked rather than waiting
- It's growing fast, changing, ulcerated, or bothering your pet
- It's red, hot, painful, or draining (possible abscess)
- Multiple new lumps, or your pet seems unwell
When it's more serious
- That can be an abscess or infection — see a vet promptly.
- Fast-changing lumps should be sampled soon — book a visit.
What your vet may do
- Examine and measure the lump
- Sample it with a fine needle (cytology) to find out what it is
- Recommend removal and biopsy if needed
- Drain and treat an abscess
Questions to ask your vet
- Can we sample it today to know what it is?
- Does it need removing, and how urgently?
- What should make me come back sooner?
- Should we map and monitor multiple lumps?
Frequently asked questions
What causes lumps & masses in cats?
A new bump or growth on or under the skin. Many lumps are harmless (like fatty lumps), but you can't tell benign from serious by feel alone — any new, changing, or fast-growing lump should be checked. Common causes include: Benign fatty lumps (lipomas) or cysts; Warts or insect-bite reactions; Abscesses (infected swellings); Skin tumors, including some cancers.
Is lumps & masses in cats an emergency?
Book a veterinary visit soon. See a vet right away if: Any new lump — get it checked rather than waiting; It's growing fast, changing, ulcerated, or bothering your pet; It's red, hot, painful, or draining (possible abscess); Multiple new lumps, or your pet seems unwell.
What can I do at home for a cat with lumps & masses?
Note the size, location, and date you found it; watch for changes Take a photo and measure it so your vet can track growth Don't squeeze, pop, or apply home remedies
Sources
Reviewed by the Webvet Veterinarian Team
This guide is general information, not a diagnosis, and does not replace an exam by your veterinarian. If your pet is in distress, contact your vet or an emergency clinic right away.