Lumps, Bumps, Cysts & Growths on Dogs

6 min read


Types of Lumps and Bumps


Lumps and bumps on a dog's skin can have many underlying causes, which owners often divide into two categories: cancer and everything else.


Non-cancerous lumps

Non-cancerous lumps commonly found on dogs include cysts, warts, infected hair follicles, and hematomas (blood blisters). While generally less worrisome to owners, non-cancerous lumps can still create discomfort for dogs. Your veterinarian can tell you which can simply be monitored and which should be treated.


Cancerous lumps

Cancerous growths on dogs can be either malignant or benign, and occasionally even share characteristics of both. Malignant lumps tend to spread rapidly and can metastasize to other areas of the body. Benign growths tend to stay in the place of origin and do not metastasize; however, they can grow to huge proportions (see such an example of an inoperable tumor pictured on the right).


Mammary gland tumors, mast cell tumors, cutaneous lymphosarcoma, malignant melanoma, fibrosarcoma, and many other types of cancers are commonly diagnosed in dogs.




The most common methods of diagnosing lumps and bumps in dogs are listed below. 


Impression Smears

Some ulcerated masses lend themselves to easy cell collection and identification by having a glass microscope slide pressed against the raw surface of the mass. The collected cells are dried and sent to a pathologist for staining and diagnosis. Sometimes the attending veterinarian will be able to make a diagnosis via the smear; but if not, a specialist in veterinary pathology will have the final say.


Needle Biopsy

Many lumps can be analyzed via a needle biopsy rather than by tissue biopsy. A needle biopsy is performed by inserting a sterile needle into the lump, pulling back on the plunger, and "vacuuming" in cells from the lump. The collected cells are smeared onto a glass slide for pathological examination. Usually the patient isn’t even aware of the procedure. 


Tissue Biopsy

Sometimes microscopically examining a larger chunk of tissue is necessary to reach a diagnosis. The mass may be totally removed or just a small piece taken out (biopsied) to give the veterinarian all the information he or she needs to make a plan for treatment.


CT Scans or MRIs

Diagnosing superficial lumps and bumps typically does not require a CT scan or MRI, so these procedures are usually reserved for internal organ analysis. If a superficial malignant tumor is diagnosed, however, a CT scan or MRI can be helpful in determining if metastasis to deeper areas of the body has occurred.




Radiography and Ultrasonography

As with CT scans and MRIs, X-ray and ultrasound evaluations are generally reserved for collecting evidence of internal masses or metastases.