Does Your Dog Have a Lump? It Grows and Shrinks? Here's What You Need to Know! (Dog Mast Cell Tumor)
Have you ever been startled by a hard or soft lump on your dog’s skin or body while petting them? Most of the time, it’s a harmless benign tumor like a lipoma. However, some lumps can suddenly grow and shrink within hours or days. If you notice this, don’t ignore it and make sure to consult your veterinarian.
Unlike simple lipomas, some lumps may be Mast Cell Tumors (MCT), a malignant growth. Mast cell tumors are one of the most common skin tumors in dogs, and their appearance varies greatly. It can be difficult to accurately diagnose just by looking, even for professionals. However, early detection and appropriate action are crucial for your dog’s health and prognosis.
What Is a Mast Cell Tumor in Dogs?
Mast cells are immune cells that play a role in allergic reactions, releasing substances like histamine to trigger inflammation. Mast cell tumors occur when these mast cells grow abnormally and excessively. They are one of the most common malignant skin tumors in dogs.
Which Dogs Are More Likely to Get Mast Cell Tumors?
- Breeds at risk: Pugs, Boston Terriers, Boxers, Labrador Retrievers, Shar Peis, Golden Retrievers, Staffordshire Terriers, Weimaraners, Bulldogs, Beagles, etc.
- Age most commonly affected: Mast cell tumors tend to occur in middle-aged to older dogs, around 8 to 9 years old, but can also appear in younger dogs.
Signs You Should Never Ignore for Mast Cell Tumors
- The lump changes size frequently: This is due to histamine secretion, which causes swelling and inflammation, making the lump fluctuate in size over hours or days.
- Redness, ulceration, or oozing: The skin around the lump may become red, ulcerated, or even start to ooze.
- Your dog constantly licks or scratches the lump: This may indicate that the lump is itchy and causing discomfort.
- Multiple lumps on the body: Mast cell tumors often appear as multiple lumps simultaneously.
- Systemic symptoms such as vomiting, loss of appetite, or lethargy: Histamine released by the tumor can affect the gastrointestinal system, causing these symptoms.
How Is a Mast Cell Tumor Different from a Lipoma?
| Feature | Lipoma | Mast Cell Tumor |
|---|---|---|
| Texture | Soft | Soft or firm |
| Size changes | Rarely | Can change |
| Surface | Normal skin | Red, ulcerated, or oozing possible |
| Itchiness | None | Possible |
| Number | Usually 1 | Can be multiple |
How Is Mast Cell Tumor Diagnosed?
The diagnosis process includes the following:
- Fine Needle Aspiration (FNA): A simple test where a needle is used to collect cells from the lump, which are then examined under a microscope.
- Histopathology and Grading: Once a tumor is confirmed, a biopsy is taken to determine its malignancy grade (GI to GIII) and decide on the treatment plan.
- Imaging Tests: If the tumor is suspected to be high-grade or metastasized, X-rays or ultrasound may be used to check for spread.
How Are Mast Cell Tumors Treated?
Treatment options depend on the tumor grade and stage:
- Surgical Removal: Low-grade mast cell tumors can often be treated successfully with surgery.
- Chemotherapy and Radiation: High-grade or metastatic tumors may require chemotherapy or radiation therapy.
- Medication: Antihistamines may be prescribed to reduce gastrointestinal issues caused by histamine secretion.
Key Takeaways for Dog Owners
- If you notice a new lump or changes in an existing lump’s size or shape, suspect a mast cell tumor and visit your veterinarian immediately.
- Do not assume it is just a lipoma based on appearance alone.
- Fine Needle Aspiration (FNA) is the most important initial test for differentiating mast cell tumors and is quick and inexpensive.
- Early detection and prompt treatment are crucial, and regular check-ups are necessary after treatment.
