If the melanoma invades the blood vessels this can result in rapid and usually fatal bleed. It will often look like a splash of black paint. Melanoma is most commonly found overlying the maxillary artery or other major blood vessels within the guttural pouch. These look like tiny black spots and are most often on the outer surface. ![]() Many grey horses will have at least some melanosis (black areas) visible on the lining of the guttural pouch. The presence of melanosis or melanoma within the pouches indicates that multiple areas may be affected and the treatment plan may have to be radically altered. These lesions usually represent secondary spread from a melanoma in the skin.Īny horse with melanoma in the skin should have its guttural pouches examined using an endoscope prior to treatment. They can become extremely large without causing any airway obstruction. Melanoma masses are commonly found in the throat/parotid region where they may involve the lymph nodes and parotid salivary gland. However samples taken from the suspected melanoma, either by a needle or by an excised piece of tumour, will usually confirm the diagnosis however. The clinical appearance of melanoma is usually so distinctive that in most cases tissue sampling for histological confirmation is probably not necessary. Sometimes melanomas lose their colour, becoming grey/blue then beige and finally red/pink in colour.Ĭonditions that could resemble or be mistaken for melanoma include other cutaneous nodular diseases such as sarcoid and carcinoma, as well as other internal neoplasms. Melanomas may bleed and exude a black tarry jelly like material. As they become more dangerous they can get bigger and merge into larger areas of tumour.įaster growing lesions, and those that have been damaged or injured may ulcerate and expose a black soft tissue. One tumour may grow at an alarming rate while those adjacent may remain stable in size. They may form chains and can vary widely in size. Melanomas usually start as small, solid, spherical lumps in and under the skin. Melanomas are small, isolated nodules with a very black colour. In some horses melanoma can become highly malignant and can spread to the internal organs which has a very poor prognosis for the affected horse. Small melanomas can be highly malignant and large ones benign or vice versa. The size of the tumour does not determine if it is malignant or not. In grey horses they are more likely to be present in large numbers and may occur in clusters. They are usually a single, isolated lesion. Melanomas that arise in horses that are NOT grey tend to be more dangerous. In some this happens quickly whilst others may be benign for a long time before they transform into a malignant form. More than 80% of melanoma lesions will become malignant at some point. ![]() Whilst the majority are benign they can become malignant and their locations can have implications for the horses welfare. Horses can develop melanoma at any age – some can even be present at birth!Īs melanomas are very common in grey horses, many people think they must be benign, incidental skin tumours. More than 80% of grey horses will have at least one melanoma during their lives. Melanoma is a very common nodular skin disease of older grey horses (usually over 7-8 years of age).
0 Comments
Leave a Reply. |