Cat Lump on Side of Neck: When to Biopsy
You are petting your cat and your finger hits a bump. Panic sets in. Wait. 90% of neck lumps in outdoor cats are not cancer.
The #1 Cause: Cat Bite Abscess
If your cat goes outside, they likely got into a fight.
- The Feel: Soft, fluid-filled, hot to the touch.
- The Behavior: The cat flinches (it hurts).
- Treatment: It needs to be lanced and drained by a vet + antibiotics.
The #2 Cause: Swollen Lymph Nodes
Just like you get swollen glands when you have a cold, cats get submandibular lymph node swelling from dental infections.
- The Feel: Firm, movable (like a grape under the skin), usually on both sides.
- Treatment: Dental cleaning/extraction of the rotten tooth.
The #3 Cause: Injection Site Sarcoma (ISS)
This is the bad one. If the lump is at the site of a previous vaccine (usually lower down the neck/shoulder).
- The Rule (3-2-1 Rule): Biopsy if:
- Persists for 3 months.
- Is larger than 2 cm.
- Increases in size 1 month after vaccination.
The #4 Cause: Thyroid Tumor
Small nodule on the windpipe.
- Sign: Cat is losing weight but eating voraciously (Hyperthyroidism).
Conclusion
If it's hot and painful -> Abscess. If it's hard and growing -> Biopsy ASAP.