A keratoma is a tumor of the keratin-containing tissue and squamous epithelial cells of the inner hoof wall. They develop as cylindrical or spherical-shaped masses, ranging in size from 0.5-2 cm (0.20-0.78 in) in diameter. Keratomas are usually found growing beneath the rigid hoof wall or sole of the foot. As these tumors grow in size, they will start to press into sensitive laminae tissue, and against the coffin bone. This will eventually result in the horse developing chronic recurrent abscesses, caused by the pressure necrosis of the tumor growth. Some horses may also show signs of abnormal hoof growth overlying the affected region or there may be a visible deviation of the coronary band. Keratoma treatment may require surgical removal of the tumor in cases where the tumor growth has resulted in abnormal hoof growth.