🩺 Vet Guide 2025: Lipomas in Dogs and Cats – Diagnosis, Types & Treatment 🐾

By Dr Duncan Houston, BVSc

Finding a lump on your dog or cat can be scary—but not all masses are dangerous. Lipomas, or benign fatty tumors, are among the most common non-cancerous growths seen in pets, especially older dogs. While they’re usually harmless, some lipomas can grow large or occur in tricky locations. In this guide, we’ll explain what lipomas are, how they’re diagnosed, when removal is needed, and how to distinguish them from more serious tumors. 🐶🐱

🔍 What Is a Lipoma?

A lipoma is a benign (non-cancerous) tumor made of fat cells. These fatty lumps grow under the skin or within muscle tissue, forming a soft, rubbery mass that’s usually movable and not painful. Lipomas don’t metastasize (spread to other parts of the body), but some may grow large or appear in inconvenient spots. 🎯

Key Characteristics:

• 🟡 Soft, rounded, slow-growing mass under the skin
• 🐾 Typically found on the chest, armpits, thighs, or abdomen
• 🧓 Common in older, overweight dogs
• 🐱 Rare in cats, but still possible

🧬 Why Do Lipomas Form?

The exact cause of lipomas is unknown, but several factors may contribute:

• ⚖️ Obesity or fat metabolism changes
• 🧬 Genetics or breed predisposition
• 📈 Age (middle-aged to senior dogs)

Any body tissue can develop a tumor—and fat tissue is no exception. Fat cells (lipocytes) can multiply abnormally and form a lump that grows independently of the surrounding fat layer. 🧪

🧪 Diagnosing a Lipoma

Even though lipomas are often easy to identify, proper diagnosis is essential to rule out cancerous lookalikes like mast cell tumors or soft tissue sarcomas. Your veterinarian may recommend:

• 💉 Fine Needle Aspirate: A sample of cells taken with a syringe, examined under a microscope for fat droplets
• 🔬 Biopsy: Removal of tissue for lab analysis, especially if the mass has unusual characteristics

Note: Lipomas feel soft and movable, while malignant tumors are usually firm, fixed, or fast-growing. Always have new lumps checked! 🧠

✂️ Should a Lipoma Be Removed?

In most cases, removal isn’t necessary unless the lipoma is:

• 📍 Growing rapidly
• 🚫 Interfering with movement or comfort
• 🔄 Becoming ulcerated or inflamed
• 🧠 In an area difficult to monitor (like armpits or groin)

Surgery is usually straightforward. Most lipomas are easily “peeled out” through a small incision. Dogs typically recover quickly. 🐶

📚 Types of Lipomas

1️⃣ Standard Lipoma

Subcutaneous, soft, slow-growing, and benign. These are the most common and often left alone unless bothersome. ✅

2️⃣ Infiltrative Lipoma

• 🧬 Grows into surrounding muscles and tissues
• ⚠️ Difficult to remove completely
• 📈 Has a higher recurrence rate (~36%)

3️⃣ Liposarcoma (Malignant)

• 🚨 Rare cancerous version of fatty tumors
• 🔬 Requires wide surgical excision
• 🧪 May need biopsy to confirm diagnosis

Reminder: Needle aspirates can’t always distinguish lipomas from liposarcomas—biopsy may be necessary for deep or atypical lumps. ⚠️

🩺 Tumors That Can Mimic Lipomas

Some malignant tumors can feel like lipomas and should always be ruled out:

• 🎨 Mast cell tumors: Inflammatory and potentially malignant
• 🔴 Hemangiopericytoma: Soft tissue sarcoma
• 🦠 Other sarcomas: May contain fat and confuse aspiration results

If a lump feels firm, fixed, or atypical—don't wait. Get it checked. ✅

📲 Ask A Vet for Lump Concerns

Not sure if that lump is harmless or not? Use AskAVet.com to upload photos, get expert advice, and decide what to do next. 🩺

The Ask A Vet App lets you:

• 📸 Share lump locations and monitor growth
• 🧪 Ask about diagnostic steps like biopsy or aspirate
• 📅 Plan for rechecks or removal when needed

Peace of mind for every lump, big or small. 📱

📝 Final Thoughts

Lipomas are usually harmless, but that doesn’t mean they should be ignored. Regular monitoring, weight management, and early diagnosis are key. Always have new or changing lumps examined by your vet. 🐶🐱

Need help now? Visit AskAVet.com for quick, expert support from licensed vets. Better safe than sorry when it comes to your pet’s skin and comfort. 🐾