Histiocytic sarcoma is a very aggressive tumour that can quickly become invasive to surrounding tissue. It has a high rate of spreading to other areas of the body. Localised histiocytic sarcoma, is often found in areas such as the skin and joints of the limbs. If this cancer has disseminated, it is in more than one area at the same time such as the spleen and lungs or the bone marrow and skin. Disseminated histiocytic sarcoma is also referred to as malignant histiocytosis or MH.
Some breeds of dogs such as the Bernese Mountain Dog, Rottweilers, Flat Coated Retrievers and Golden Retrievers, are at higher risk of this type of cancer.
Histiocytic sarcoma is a cancer formed from histiocytes. These are cells that are part of the immune system and work by telling white blood cells what to attack. When they turn cancerous they can very quickly travel to other parts of the body.
The best treatment of localised histiocytic sarcoma, when the tumour is on the skin, is the removal of the tumour. If there is enough risk of cancer left behind at the surgery site or suspected elsewhere, then surgery can be followed by chemotherapy or radiation to kill any remaining cancer cells. The prognosis of this is good if caught early enough, before it has spread to other organs. If the tumour was on another organ such as the spleen, the long term prognosis (more than a year) is poor.
Treatment for disseminated histiocytic sarcoma is effective in controlling disease and improving quality of life around half the time, typically for a maximum of 12 months. Chemotherapy is the choice of treatment as surgery and radiation are not an option. Good care and nutrition can improve quality of life. Without help, normally an affected dog will not survive more than a couple of months and usually it is much less.
**Accuracy checked 19 June 2013,
Dr Ken Wyatt BSc BVMS FANZCVS,
Registered Specialist in Veterinary Oncology,
Perth Veterinary Oncology
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