Our canine companions develop all sorts of lumps and bumps, most of them harmless. But others can cause a whole heap of trouble.

Mast cell tumors arise from immune cells throughout the body. Normal mast cells fight parasites and orchestrate allergic reactions. But for unknown reasons, they sometimes morph into cancer cells and form tumors, particularly in the skin.

While some mast cell tumors grow rapidly, turn red or fill with fluid, many look just like any other lump. Many veterinarians will note the location and size of a dog’s bumps at each checkup and collect cells from any new or changing ones to determine their type.

Mast cell tumors can be deadly if not removed. So protect your pooch by staying vigilant for new or changing lumps and bumps.