Mineralization of the tumor is common. In pigs and cattle, mast cell tumors are rare. They tend to be solitary and benign in pigs and multiple and malignant in cattle. Mast cell tumors are found in the skin of cattle most commonly, but these may be metastases from tumors of the viscera. Other sites in cattle include the spleen, muscle, gastrointestinal tract, omentum, and uterus. Dogs
Mast cell tumors mainly occur in older adult dogs, but have been known to occur on rare occasions in puppies. The following breeds are commonly affected by mast cell tumors:

Boxer
Staffordshire bull terrier
Bulldog
Basset hound
Weimaraner
Boston terrier
Great Dane
Golden retriever
Labrador retriever
Beagle
German shorthaired pointer
Scottish terrier
Pug
Shar pei
Rhodesian ridgeback

Cats
Two types of mast cell tumors have been identified in cats, a mast cell type similar to dogs and a histiocytic type that appears as subcutaneous nodules and may resolve spontaneously. Young Siamese cats are at an increased risk for the histiocytic type, although the mast cell type is the most common in all cats and is considered to be benign when confined to the skin.Mast cell tumors of the skin are usually located on the head or trunk. Gastrointestinal and splenic involvement is more common in cats than in dogs; 50 percent of cases in dogs primarily involved the spleen or intestines. Gastrointestinal mast cell tumors are most commonly found in the muscularis layer of the small intestine, but can also be found in the large intestine.
The communication will allow air to be forced from the sinuses into the orbit in the presence of a pressure gradient from forceful expiratory efforts, nose-blowing or even a sneeze. Orbital emphysema is typically a harmless disorder because air escapes as quickly as it enters the fracture site, and the increase in intraorbital pressure is usually transient, lasting for as long as the sneeze or nose blowing. However, when orbital soft tissues, such as fat, falls back on the sino-orbital communication, a one-way ball valve will be created, leading to the entrapment of air. When sufficient air accumulates, it will result in acute compartment syndrome and vascular compromise, causing complications including proptosis, visual impairment, central retinal artery occlusion, compressive optic neuropathy, and other severe complications caused by orbital compartment syndrome.There are three variations of orbital emphysema, namely palpebral emphysema, true orbital emphysema, and orbitopalpebral emphysema. Palpebral emphysema
Palpebral emphysema refers to emphysema of the eyelids alone. It is a rare kind of orbital emphysema which is usually caused by fractures of the lacrimal bone. The lacrimal sac ruptures as a result of the fracture, allowing air from the nasal cavity to enter the tissues of the eyelid. Alternatively, facial subcutaneous air may simply pass into the eyelids along fascial plane to produce palpebral emphysema. As long as the orbital septum is intact, air is confined in the eyelids. True orbital emphysema
True orbital emphysema occurs when there is air behind an intact orbital septum.