Mast cell tumors are a type of cancer. Tumors are composed of mast cells that are normally found within the connective tissue of an animal. Mast cells are formed within the bone marrow of an animal, release histamine, and are normal components of the immune system.
Mast cell tumors are not always malignant and have varying appearances ranging from a wart-like nodule to an ulcerated mass to a small lump.
Diagnosis of a mast cell can usually be obtained by performing a fine needle aspirate or preferably with a biopsy. A biopsy will enable a grade or stage to be determined to define the tumor and tell you how malignant the tumor is.