My dog has a new lump on its leg. What could it be and is it serious?

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.

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!

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.

I am sorry to hear about Rocco. This looks like it could potentially be a tumor that has a small ulceration or wound. We can have tumors that are benign and do not spread/cause other problems, but others are aggressive and should be removed. I would recommend bringing Rocco into the vet for an exam. Your vet may try to get some cells from the tumor to examine under the microscope in order to determine the type/behavior of the growth and determine if it should be surgically removed or if it can just be monitored.

This lump could be a cyst, abscess, lipoma, benign tumor, or 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 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. Give her vet a call in the morning to make her an appointment. Best of luck.

Without further testing, there is no way to tell if this growth is a malignant (cancerous) type that can spread elsewhere and/ or invade the healthy tissue around them, or a more benign (noncancerous) type that is unlikely to spread. In some cases abscesses can form due to infection, or bumps can form due to trauma/pressure on the area or due to allergies, but in this case the picture appears to be a raised mass of some sort. I recommend making an appointment to see your vet to have the growth tested. In many cases this can be done using a fine needle aspirate, where cells are removed from the growth using a needle and examined under a microscope to determine what it is and to guide treatment. In some cases further testing may be needed to determine the necessary course of treatment, but it is important to get new growths tested in a timely manner, as some can be cancerous and quite aggressive in their growth, and growths due to infection, allergy or trauma can lead to complications or be indicators of underlying health problems. In the meantime, if Rudy begins licking the area, make sure he wears a “cone” (also known as an e-collar or Elizabethan collar) at all times when he is not being directly supervised by you, including while sleeping to help prevent infection.

Without further testing, there is no way to tell if this growth is due to infection, trauma or allergy, or if it is a mass. Masses can be of a malignant (cancerous) type that can spread elsewhere and/ or invade the healthy tissue around them, or a more benign (noncancerous) type that is unlikely to spread. I recommend making an appointment for Onxy to see your vet to have the growth tested. In many cases this can be done using a fine needle aspirate, where cells are removed from the growth using a needle and examined under a microscope to determine what it is and to guide treatment. In some cases further testing may be needed to determine the necessary course of treatment, but it is important to get new growths tested in a timely manner, to allow for treatment if necessary.