Etiology

• Malignant tumor of vascular endothelial cells.
• May occur as focal cutaneous masses, masses with local infiltration, internal masses restricted to one organ or disseminated neoplasia affecting multiple organs.
• Primary lesions may be impossible to define clinically, especially as they are not always the largest lesion identified in the animal.
• Reported locations (but not restricted to):
  • Skin, subcutis, skeletal muscle and bone, extradural spinal canal and brain and urinary bladder.
  • Metastatic spread to lungs, lymph nodes, gut, peritoneum, spleen, liver and kidneys.
• Skin forms manifest as skin nodules with a highly vascular appearance that bleed readily upon even minor trauma.
• In canines, cutaneous vascular lesions are often less aggressive (hemangiomas) but these may still be malignant and locally invasive. There is insufficient evidence to know if this is also the case in cattle.
  • In canines, it has been hypothesized that the cutaneous form may be solar induced, but it is again unclear whether this also occurs in bovines.
• Clinical signs caused by hemagiosarcomas vary according to their location.
• Internal forms of the tumor can have vague or sometimes unrelated signs such as partial intestinal obstruction, along with organ changes and bleeding (urinary bleeding/intestinal bleeding).
• Disseminated forms of the tumor can present with inappetence and weight loss, along with anemia and thrombocytopenia.
  • Cattle may also become icteric if the liver is affected.
  • Coagulopathies may also develop if platelets are consumed or there is suppressed production (platelet count low), potentially causing disseminated intravascular coagulation.
• Muscular forms are commonly presented with limb swelling/edema:
  • There is often painful, marked and progressive muscle swelling.
• In canines, the tumor has been reported to affect the nervous system, but there is little evidence of this in cattle.

Timecourse

• Rapid progression.
• Early lesions often not detectable, leading to delays in treatment application
  • Many lesions are untreatable by this point, and outlook is bleak.
  • However, there are a small number of reports detailing successful early intervention and local treatment success.