Changes

*The lesions are proliferative to degenerative, depending on the virus strain.   

*The lesions are proliferative to degenerative, depending on the virus strain.   

*The skin tumors result from proliferation of undifferentiated mesenchymal cells which become large stellate cells (myxoma cells).  These cells may contain intracytoplasmic eosinophilic inclusions. These cells lie in a homogeneous matrix of mucinous material interspersed with capillaries and inflammatory cells.  Endothelial proliferation with narrowing of the lumen and extrusion of stellate "myxoma" cells has been described.   

*The skin tumors result from proliferation of undifferentiated mesenchymal cells which become large stellate cells (myxoma cells).  These cells may contain intracytoplasmic eosinophilic inclusions. These cells lie in a homogeneous matrix of mucinous material interspersed with capillaries and inflammatory cells.  Endothelial proliferation with narrowing of the lumen and extrusion of stellate "myxoma" cells has been described.   

*Epithelial cells overlying the tumor may show hyperplasia or degeneration, or may appear normal.  Epithelial proliferation is characterized by ballooning of cells in the stratum granulosum and hyperkeratosis.  Epithelial vesiculation progresses to crust formation.  Large, eosinophilic, intracytoplasmic inclusions are especially prominent in the stratum spinosum.  Lesions in other organs include cellular proliferation of alveolar epithelium and the reticulum cells of lymph nodes and [[Spleen - Anatomy & Physiology|spleen]].  Focal hemorrhage may be present in skin, kidneys, lymph nodes, testes, heart, stomach, and intestinal walls.  Myxoma cells may be present in lymph nodes, bone marrow, uterus, ovaries, testes, and lungs.

*Epithelial cells overlying the tumor may show hyperplasia or degeneration, or may appear normal.  Epithelial proliferation is characterized by ballooning of cells in the stratum granulosum and hyperkeratosis.  Epithelial vesiculation progresses to crust formation.  Large, eosinophilic, intracytoplasmic inclusions are especially prominent in the stratum spinosum.  Lesions in other organs include cellular proliferation of alveolar epithelium and the reticulum cells of lymph nodes and [[Spleen - Anatomy & Physiology|spleen]].  Focal hemorrhage may be present in skin, kidneys, [[Lymph Nodes - Anatomy & Physiology|lymph nodes]], testes, heart, stomach, and intestinal walls.  Myxoma cells may be present in [[Lymph Nodes - Anatomy & Physiology|lymph nodes]], [[Bone Marrow - Anatomy & Physiology|bone marrow]], uterus, ovaries, testes, and lungs.

====Shope fibroma virus====

====Shope fibroma virus====