My dog has a large lump near his back leg. What is it? Should I worry?

You are correct that lipomas generally grow very slowly. I recommend to have Jackson examined today. A rapidly growing bump is worrisome for an abscess, a foreign body reaction, an infected cyst or an aggressive cancer. Protect the area from licking by having Jackson wear an elizabethan collar at all times. Protect the area from trauma and have him examined today by the veterinarian. I hope this helps.

That is a large, lobulated lump (no just one defined lump) in a location that would generally never have something like a swollen lymph nodes. I recommend making an appointment with your vet for a fine needle aspirate (where they aspirate cells from the mass and put them on a slide to be sent out for review) to determine if it is an abscess or a tumor/cancer of some sort. Best wishes for Diesel!

I would have this lump on Jake examined by a vet. It could be a cyst, a benign tumor, or potentially a malignant tumor. Any suspicious lumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of it's cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. I'd recommend having Jake seen by a vet tomorrow to have the lump examined and diagnose so it can be treated as needed.

Without a physical exam or diagnostics, it is difficult to determine if this is something to worry over. Ideally, a fine needle aspirate or biopsy should be done to collect samples for pathology. This may provide a diagnosis. X-rays of the limb may be recommended to rule out bony involvement. Since you state it is growing, it should be removed before it becomes too large. As it is, that is a difficult area to close after a mass removal.

This can be a benign lump, or it could be a lipoma or cyst. Any suspicious lumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of its cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. Once the cause of the lump is diagnosed, the vet can discuss treatment options if needed. I'd give his vet a call tomorrow to make him an appointment. Best of luck.

This could be a seroma from an injury, a cyst, abscess or a tumor. Cysts and abscesses need to be drained by a vet. If your vet suspects a tumor, he will do a fine needle aspirate to determine whether it is a harmless lipoma, which does not need to be removed unless it is ulcerating or bothers the dog due to its location or size, or another tumor that needs to be removed. Please make an appointment with your veterinarian for an exam of the mass.

Looking at the photo and considering your description of the progression of this, I would suspect that it is a growing mass. It could simply be a fatty lump such as a lipoma. Other possibilities would be a soft tissue swelling due to trauma, but this seems less likely considering the progression. I would head to the vet and get them to test the lump to see exactly what it is. If it is just a lipoma and not causing bother it should not need to be removed.