Q: Our cat/dog has a bump on her side that we have noticed recently. We do not think it really bothers her. It is about the size of a pea. Should we have the veterinarian take a look or should we just watch it?

A:Though a pet may develop a mass on or under the skin at any age, older pets are generally more likely to have "lumps and bumps." These lumps and bumps can vary from tumors that require surgical removal to benign cysts that barely enlarge as the years go by. Unfortunately many malignant tumors begin with the same appearance as benign bumps.

Some masses can be identified on site but most need to be investigated. The most common way a mass is investigated is with an aspirate. This involves using a needle to try to remove some cells from the mass for identification. The cells are usually taken from the needle and put on a microscope slide to try to identify the cell type. Aspirating does not always work (some masses do not shed cells well) but is a good first step. If an aspirate cannot identify the mass the next step is usually a biopsy or surgical removal.

Many masses are benign and can just be observed for changes or enlargement. Malignant masses that are identified when small are easier to remove completely. The earlier a malignant mass is removed the less the chance of metastasis (movement to other parts of the body) as well. Remember you can always observe a mass over time if the aspirate indicates it is benign. If a mass is malignant you want to know as soon as possible.

Erik Dorsch is a veterinarian at The Animal Hospital in Carrboro.