In dogs and cats, the most common primary sites of this cancer are spleen, liver, heart and skin. (vetspecialists.com)
Although the skin is the most common primary site for MCTs in this species, they can arise from anywhere in the body. (wearethecure.org)
In contrast, it is rare when patients with spleen HSA are cured following surgery to remove the spleen as tumors that arise in that site are usually associated with metastasis (spread of tumor cells from primary site via the blood stream to new locations such as lung). (vetspecialists.com)