Histiocytic sarcoma arises as a result of the excessive and abnormal proliferation of a population of histiocytes, a type of immune cell. The underlying cause for this disease is unknown; however, hereditary factors are suspected based on the aforementioned breed predispositions. Because histiocytic sarcoma is a type of immune cancer, this type of cancer can be found in many locations throughout the body. Therefore, the clinical signs of histiocytic sarcoma depend upon the tissue or organ affect