Mast cell tumors can arise from any skin site on the body, and can have a variety of appearances. Veterinary oncologists recommend that before any skin lump is removed, the cells from the mass be collected for examination to rule out the lump as a mast cell (or other malignant) tumor. And mast cells are something that are easily identified on aspiration.
What you might see (clinical presentation of mast cell tumors)
MCT most commonly are seen as solitary lumps or masses in or underneath the skin; occasional dogs can have multiple masses from MCT. MCT can look like just about anything, ranging from benign-appearing lumps (such as a lipoma), to more angry or ulcerated lumps, masses with a stalk or focal thickenings in the skin. MCT may change quickly in size (become larger then smaller ) because of reactions around the mass. Some dogs may have signs of systemic disease, which can be caused by some of the biologically active compounds found within mast cells. In most cases, evidence of a MCT is easily generated by examination of a fine-needle aspirate of the suspect mass, and aspiration is advised before removal of a mass to be sure it is not a MCT (or other skin malignancy), a finding that would demand a more aggressive surgical removal. Often, obtaining blood for a complete blood count and biochemical profile, and a urinalysis will be advised as these can help assess overall health and provide information that potentially influences treatment recommendations.
NB: Rapid removal is the current treatment of choice. My experience is that these tumors often occur in patients with sufficient vitality such that removal of one tumor often results in another. Or two new tumors. Sometimes tumors which are more malignant result. Homeopathy can help, both before and after surgery.--Dr. Jeff