Benign tumors of the skin are created by uncontrolled cell growth that does not harm the surrounding tissue and does not form metastases.
Benign tumors can occur in all regions of the body. Common places include the flank, the back and the neck. Areas where injections for vaccination are regularly administered, for example the neck or the flanks, can also develop knotty swellings. Generally the chance of a tumor developing is more likely the older the dog is. Benign tumors often develop in dogs older than ten years. Smaller knots are usually discovered while owners are petting or combing their dogs. Larger knots and swellings are mostly visible to the naked eye. Among the benign tumors especially the lipoma, a tumor of fatty tissue, can grow up to the size of a lemon. Smaller tumors can become as big as a nut or plum. As long as the benign tumor doesn’t cause discomfort while moving or lying down and the surrounding skin is not damaged, it shouldn’t pose an immediate problem.
All body cells are normally subject to the mechanism of controlled growth. If this mechanism is impaired, the cell may grow excessively and form a lump. The underlying causes can include radiation, injected medication, poisoning, prolonged tissue damage or genetic predisposition. In many cases, the cause of a tumor cannot definitely be identified. The characteristics of a benign tumor are a distinct growth of only the tumor without affecting surrounding tissue. They also don’t create metastases and therefore are not a serious threat to the life of the dog. Tumors are differentiated by the kind of tissue they are formed from. For example, they may be formed from fat tissue, connective tissue, and immune cells. Common benign tumors among dogs are the lipoma, a benign tissue of formed form fat tissue, the fibroma, which comes from connective tissue, or warts. For more detailed information on different forms of benign tumors see the related diseases section.
Whether a tumor is malignant or benign can only be determined by a thorough examination of a tissue sample. In order to perform the examination, a small piece of the tumor is extracted and analyzed in the laboratory. The characteristics of different tumor cells can are then determined by using a microscope. Any categorization by speed of growth or size is usually not possible or meaningful. The surgical removal of a benign tumor is only advisable if it affects sensitive skin areas, or is damaging the skin.
Owners should not remove a benign tumor by themselves, because it can lead to injuries and infections of the dog’s skin. In general, keep an eye on the affected area and consult a veterinarian.