I had to do some reading to find out about mast cells. According to the Cornell Book of Cats, mast cell tumor is the fourth most common of skin tumor of the cat. The mast cell is a connective tissue cell that plays a role in normal inflammatory responses and in allergy. This tumor is especially common in older male cats. It can occur anywhere in the skin, but has a predilection for the head and neck. Mast cell tumors can take a variety of forms. The majority are benign, but some are agressive, malignant growths that spread to the lymph nodes, liver, spleen, and lungs, usually within three to six months.
Therapy of the solitary mast cell tumor consists of surgical excision.
Hopefully the results will be in by Monday.