A number of skin tumors can occur in cats, and most owners will find unexplained lumps and bumps on their pet at some point during its life. While skin tumors can be harmless, sometimes they are malignant or proliferative and invasive and deserve prompt medical attention. A veterinarian is the best person to assess skin tumors and determine if a given bump is a benign pimple, cyst, skin tag or abscess, or if instead it is cancerous and much more serious. One of the most common initial procedures used to assess skin tumors is a fine needle aspirate. During this procedure, the veterinarian will gently insert a needle into the lump, pull back on the syringe stopper to draw out some of the fluid and cells inside the mass and then “squirt” the sample onto glass slides for microscopic examination. Other diagnostic procedures may be required as well.