Finding an unexpected lump on your senior pet while grooming or petting them can be concerning. Most masses found on pets are innocuous fatty tumors, but your pet’s risk for a more serious issue increases as they get older. The only way to definitively know if your senior pet’s lesion is benign or malignant is to have the lump evaluated by a veterinary professional.

How does my veterinarian know if my senior pet’s lump is serious?

Your veterinarian will perform a thorough physical exam on your senior pet, and examine the lesion closely.  You should be prepared to provide any information you know, such as when you first noticed the lump, whether the lesion’s shape, color, or size has changed, and if your pet’s appetite or energy level has decreased. Your veterinarian may want to perform blood work on your pet. They will also test the lesion using the following diagnostic procedures.

* Fine needle aspiration (FNA) — After thoroughly cleaning the area, your veterinarian will insert a needle in the lump and aspirate cells, which will be evaluated under a microscope to determine the lesion type. A cell sample may also be sent for culture to test for infectious agents, such as fungi or bacteria. About 95 percent of masses can be diagnosed using FNA.

* Biopsy — If the FNA does not confirm a diagnosis, your veterinarian will perform a biopsy of the mass that will be sent to a pathologist for evaluation. If the lesion is small, the entire mass will likely be removed, but if the lump is large, a small portion will be removed for analysis.

What benign lumps can affect my senior pet?

A benign lesion does not have the ability to invade other tissues and cannot spread (i.e., metastasize) to other sites. However, they can cause problems if they become too large, or are in a location restricting mobility. If your senior pet continually scratches at the lesion, removal should be considered, to prevent chronic skin infections. Benign tumors include:

* Lipoma — The most common benign masses found in senior dogs are lipomas. These lesions are composed of fat cells, and are soft and easily moveable under the skin. Your veterinarian may recommend removal if their location may restrict your senior pet’s movement or if they are growing quickly.

* Basal cell tumor — The most common benign skin lesions found in senior cats are basal cell tumors. They are small, firm masses usually found around a senior cat’s head and neck.

* Abscess — These lesions contain purulent fluid (i.e., pus) caused by infection. The abscess will need to be drained and lavaged using an antibacterial solution. Your senior pet may require systemic antibiotics to help resolve the problem.

* Sebaceous adenoma — These sebaceous gland tumors appear as multiple wart-like growths. They can be found anywhere on the body, but the head is a common location.

What malignant bumps can affect my senior pet?

Malignant growths can enter the bloodstream or lymphatic system to spread throughout the body and affect sites such as the brain, bones, lungs, and liver. Malignancies should be removed as soon as they are diagnosed, to help prevent metastasis. Chemotherapy and radiation therapy may be employed to help prevent further spread. Malignant masses include:

* Squamous cell carcinoma (SCC) — Caused by sun exposure, SCC affects unpigmented, thinly-haired areas, such as eyelids, lips, nose, and vulva. SCC rarely metastasizes to other locations, but can aggressively invade surrounding tissue. Prognosis is best when surgical removal and radiation begin early.

* Mast cell tumor — These are the most common malignant tumors seen in senior dogs, but can also affect cats. Mast cell tumors can metastasize to other organs, such as the spleen, liver, and bone marrow. Your veterinarian may order chest X-rays or an abdominal ultrasound to check for metastasis.

* Fibrosarcoma — While these tumors do not tend to metastasize, they typically are locally aggressive and quickly invade the surrounding tissues. Removal can be difficult, and treatment usually requires a combination of surgical excision, radiotherapy, and chemotherapy.

* Osteosarcoma — Caused by abnormal bone cell growth, unusual hormone stimulation, genetic factors, or a previous fracture in the area, osteosarcomas are the most common bone cancer diagnosed in senior cats and dogs. Osteosarcoma is exceptionally aggressive and commonly spreads to the lungs, so early detection and treatment is important to prevent metastasis.