Found a lump on my 11-yr-old Cocker Spaniel last night while petting her. Right side, just behind the shoulder blade, under the skin. Pea-to-marble sized, firm but moves slightly when I push it, doesn’t seem painful when I press. Skin over it is normal — no redness, no hair loss.
She’s acting completely normal. Eating, going on her walks, no weight loss.
I know ‘any new lump in a senior dog should be checked’ but I’m trying to gauge urgency. Is this a ‘book the vet next week’ or a ‘tomorrow morning’ situation?
You're right that any new mass in a senior dog deserves evaluation. The reassuring features in your description (well-circumscribed, mobile, non-painful, no skin changes, dog systemically well) are most consistent with a benign lipoma — the single most common subcutaneous mass in older dogs — but you cannot diagnose this by feel alone. Mast cell tumors can present identically and the textbook warning is “every lump can be a mast cell tumor until cytology says otherwise.”
The gold-standard first step is a fine needle aspirate (FNA) with cytology. It's quick, low-cost (typically $80-150 with cytology read), and gives you a definitive answer in 2-5 days for the common diagnoses:
- Lipoma → monitor, no action needed unless mechanically interfering
- Mast cell tumor → needs excision with appropriate margins, urgency depends on grade
- Soft tissue sarcoma → surgical planning + likely imaging
- Inflammatory / cyst → treat the underlying cause
Urgency-wise: this is a “book within 1-2 weeks” situation, not an overnight emergency. But if you notice rapid growth, ulceration, redness, or any swelling/redness around it — that bumps it up to “this week.”
One practical thing you can do tonight: measure the lump with calipers or a ruler in two dimensions, write down the date, and re-measure weekly. A lump that doubles in 1-2 weeks is a different conversation than one that's stable for 3 months.
Reference: ACVIM/Veterinary Society of Surgical Oncology consensus on cutaneous and subcutaneous masses (2019).