- Health Library
- PetMD U
Mast cell tumors (or mastocytomas) are graded according to their location in the skin, presence of inflammation, and how well they are differentiated. Grade 1 cells are well differentiated with a low potential for metastasis; Grade 2 cells are intermediately differentiated with a potential for locally invasive metastasis; and Grade 3 cells are poorly differentiated or undifferentiated with a high potential for metastasis. Differentiation is a determination of how much a particular tumor cell looks like a normal cell; the more differentiated, the more like the normal cell. In general, the more differentiated the mast cell tumor is, the better the prognosis is.
Siamese cats appear to be more susceptible to mast cell tumors than other breeds, and are susceptible to histiocytic cutaneous (skin) mast cell tumors (where histiocytes are mature macrophages that reside in connective tissue). The mean age for the development of the mastocytic (mast cell) form occurs at mean age of 10 years in cats; the histiocytic form occurs at a mean age of 2.4 years. It has been reported in animals less than one year of age and in cats as old as 18 years of age.
Symptoms may be dependent on the location and grade of the tumor.
Symptoms are also dependent on the stage of the disease:
You will need to give a thorough history of your cat's health, including a background history of symptoms. The history you provide may give your veterinarian clues as to which organs are being affected.
The most important preliminary diagnostic test will be an examination of the cells taken from one of the tumors. This will be performed with a fine needle aspirate and will determine the presence of an abnormal amount of mast cells in the blood. A surgical tissue biopsy will be necessary for definitive identification of both the grade of the cells occupying the mass, and the stage the disease is in. Additionally, your veterinarian may examine a sample from a draining lymph node, from the bone marrow, or from the kidney and spleen. X-ray and ultrasound images of the chest and abdomen will also be component of determining the exact location and stage of the tumor's development.
The prediction of a disease’s outcome in advance
The area between the vulva and anus or scrotum and anus
The sac that holds the testes; may also be referred to as the scrotal sac
Found underneath the dermis
The genitalia of a female; found on the outside
The growth of pathogens away from the original site of the disease
Small structures that filter out the lymph and store lymphocytes
a) inhaling b) getting out fluid or gas by the act of sucking.
Not being able to cause harm; the opposite of malignant.
The process of removing tissue to examine it, usually for medical reasons.
The cutting of a piece of tissue or organ for medical examination
The end of the gastrointestinal tract; the opening at the end of the tract.