It is impossible to tell if a lump under the skin is a cyst, fatty tumor (lipoma), or malignant tumor without performing a “needle aspiration biopsy”. Early detection of a malignant mass, by this method, can be the difference between life and death. if you notice any sort of lump developing under your pet’s skin bring him or her in immediately for testing.
One of the most serious mistakes pet owners make is that they watch to see if a mass grows larger before bringing him or her into the veterinarian. The problem with waiting is that if the mass turns out to be malignant the additional waiting time may have allowed the mass to spread to the blood stream and to other organs and tissues.