What to do about those lumps and bumps PDF Print E-mail
News - Rubrieke
Thursday, 09 December 2010 21:19
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In this column veterinarian Dr Liesel van der Merwe provides practical assistance for common problems in companion animals. She is a specialist physician at the Onderstepoort animal teaching hospital and a senior lecturer in the section of small animal medicine. Send your questions to This e-mail address is being protected from spambots. You need JavaScript enabled to view it


Dr Liesel van der Merwe

Our pets often get lumps and bumps on their skin. Some of these are of minor importance and others are malignant. Here are a few guidelines.

Your veterinarian can often get a reasonable idea on what type of lump it is by examining your pet.

They take into account what the lump looks like, what it feels like, where it is found on the body, how long it took to appear and what breed, sex and age the animal is. All these things are factored into a probable diagnosis. For example, young dogs often get benign lumps called histiocyomas - the lump looks like a pink button – on their legs and faces.

Cats often get abscesses or lumps caused by allergic swelling (eosinophilic granuloma). Lipomas (fatty lumps) are common benign lumps, although they may grow very large.

If the vet wants to do further tests to try to identify the type of lump, he may take a small sample of cells using a needle (fine needle aspirate) and look at the cells under a microscope.

This is a simple procedure and can be performed in the consulting room on a wide awake animal and works well to try to differentiate between a lump caused by an infection or one caused by abnormal proliferation of cells.

The softer lumps shed sufficient cells to sometimes allow identification, but the firmer lumps often do not. The more definitive step is to take a slice of tissue from the lump, or the entire lump if it is very small and send it away to a pathologist who also examines it under a microscope. This procedure is generally performed under sedation or a full general anaesthetic.

The advantage in this scenario (histology) over an aspirate is that the cells have not been sucked out in a needle and their architecture remains intact. The histopathologist is then able to examine the tissue and determine its nature. Modern science has allowed many advances such as special stains and cell markers which help to refine the diagnosis.

If your vet has determined that the lump is benign, you may elect to leave it or have it removed, depending on the impact it has on your pet. If your vet is concerned that the lump may be malignant or the laboratory report says that the lump is malignant, the next step is to stage the cancer.

Malignancy can be interpreted in two ways: Has the cancer spread to other organs? Is it causing compromise of an organ function?

Malignant tumours will often spread to the lymph nodes, draining the region involved, the lungs, liver and spleen. Chest X-rays and a sonar (ultrasound) of the abdomen to look for smaller tumours (metastases or “mets”) are usually performed before major surgery to remove the cancer. This is what is meant by staging. The more areas a tumour has spread to the poorer the longterm prognosis becomes.

A slow growing tumour in the brain may not spread to other organs or invade surrounding tissue and may therefore not be classified as a malignant or aggressive tumour. However, the pressure it places on the brain may cause severe neurological problems and it is thus also not “benign”.

The prognosis depends on the type of tumour and the stage of spread (staging). This differs for the various types of tumours and will influence decisions about major surgery, the aggressiveness of the surgery and the addition of chemotherapy.

For example, if a bitch develops mammary tumours (breast cancer), 50% may be benign. If chest X-rays show that the lungs are also involved, the prognosis is poorer and it would be a reasonable decision not to do surgery. If surgery is performed to improve quality of life, it would be clear that the long-term prognosis is still guarded.

The bottom line is that it is important to know what these lumps are. Many are innocuous, but when removing lumps ask your veterinarian to send them away to the laboratory.

The additional cost is only about R300, but the additional information gained may be extremely important.

 

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