Myxomas are a benign neoplasia of connective tissue.
These tumors are slow growing and locally destructive tumors and can affect various organs such as blood vessels (angiomyxoma), joint tissue (synovial myxoma), kidneys, heart, teeth (odontogenic) or bone.
Odontogenic myxomas have a similarly good prognosis although surgical debridement or manbidulectomy may be required in advanced cases.
A tentative diagnosis can be made on ultrasonographic or radiographic appearance of these growths which may have mineralization as part of their neoplastic changes.
Diagnosis is based on histological examination of tissue samples. These tumors have a characteristic appearance with spindle cells in loosely packed and interlacing streams within a myxomatous stroma. The myxomatous nature of the tumors is usually confirmed by positive staining with Alcian blue and vimentin.
Immunohistochemical staining is usually positive for vimentin, von Willebrand Factor, and alpha-smooth muscle actin.
With odontogenic myxomas, surgical extirpation is usually curative, but angiomyxomas and synovial myxomas tend to progressively worsen, with survival rates of 1 - 2 years depending on location. Cardiac myxomas are usually untreatable in the veterinary setting without bypass machines allowing surgical replacement of the defective valve.
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