Squamous Cell Carcinoma The second most common type of skin cancer that is a slow growing but locally invasive malignant tumor.
The cause of squamous cell carcinoma is idiopathic but is strongly linked to
.
The tumor develops on non-pigmented skin at the
junction.
Predispositions include non-pigmented areas of skin. Breeds include Paints, Pintos, Appaloosas & Belgians. It is more common in mature horses over the age of 8 years old. It is more predominate in males. The tumors begin as a superficial red, raised nodule that ulcerates and bleeds easily. It appears as a granulomatous lesion. The lesions appear in areas where the skin meets the mucus membranes such as the , lips, ears, mouth, anus and external genitalia. The tumors are considered slow growing and usually are solitary in nature. Metastasis is uncommon but can occur late in the disease process.
Diagnosis of squamous cell carcinoma can be made through signs and symptoms and through biopsy and histology.
Treatment includes surgical excision, cryosurgery, radiation and chemotherapy. Treatment will depend on the size and location of the tumor.
Prevention is protection of non-pigmented areas from the sun.
Melanoma Melanoma is a benign tumor of
.
It is a form of neoplasia that is linked to the loss of pigment in the skin of
horses as
they age.
Melanomas are generally seen in grey coloured horses over years of age. There are more reports of melanoma in males than female horses, though no sex predilection has been shown.
Clinically melanomas are seen as smooth, raised nodules covered with skin and hair. The skin over a tumor is a normal grey or black colour. The material inside a melanoma is a greasy grey-black semi-solid. There is generally no pain or pruritus associated with melanoma tumors. Tumors are usually found in the perianal area, the underside of the tail, the genital area, the parotid gland region, the eyelids and the distal limbs, though tumors can occur anywhere melanocytes are located. May interfere with bodily functions.
Melanomas are generally slow growing tumors that remain localised for many years. Three distinct growth patterns are seen with melanomas.
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