Hemangiosarcoma is a tumor that arises from the vascular endothelium. It occurs in dogs more frequently than any other species, and unlike most neoplasia it is one tumor that has shown true genetic predilection for Golden Retrievers and German Shepherds. It can occur in cats but far more infrequently.
In a dog, the most common primary site for hemangiosarcoma is the spleen. Other frequent sites include the right atrium, liver, and skin. Grossly these tumors are of variable size and often present as a bruised, soft or gelatinous, non-encapsulated mass. When visualized in the spleen, cavitated- heterogenous-masses are noted within the mass itself. These tumors are friable and complications associated with rupture are the most common presenting complaint.
History and clinical signs
Presenting complaints vary from nothing where the mass is found incidentally to ataxia, weakness, and pallor. Occasionally, patients will present with a history of waxing and waning weakness that has persisted for weeks. Other vague clinical signs such as lethargy, weakness, and ADR are generally associated with large masses and the secondary inflammation and/or necrosis that goes along with them. Dogs with cardiac hemangiosarcoma present with signs of tamponade such as collapse or right-sided heart failure such as dyspnea, exercise intolerance, and ascites.
3 view chest radiographs and a thorough evaluation of the abdomen via ultrasound or CT scan is recommended since this tumor has a high incidence of metastasis. In patients who present symptomatically, 75% of cavitated splenic masses are malignant while the other 25% are benign. While many criteria have been evaluated, malignancy cannot be determined based on ultrasound alone. However, in one study evaluating incidentally noted splenic nodules or masses, 75% of these were noted to be benign. Screening for metastasis is mandatory prior to going to surgery since prognosis is markedly decreased with metastatic disease.
The treatment involves dealing with the local disease as well as staving off any future metastasis, including surgery to remove the spleen or localized tumor. Average survival times with splenectomy alone are around 3 months. Adjuvant chemotherapy with Doxorubicin or Carboplatin has an average survival time of 6-8 months. Pericardectomy for cardiac hemangiosarcoma can be performed with average survival times of around 3 months. Renal, conjunctival, and some retroperitoneal hemangiosarcomas may have a longer prognosis. Adjuvant treatments with Turkey Tail mushroom have shown promise with hemangiosarcoma and are complementary to more traditional therapies.
Dermal hemangiosarcomas are most noted on the sparse haircoat areas of sunbathing dogs. They tend to be numerous and superficial. Surgical removal of bloody masses or ones that bother patients are warranted and prognosis is generally excellent. However, if skin and subcutis hemangiosarcomas delve deeper into underlying tissues such as subcutaneous or musculature, the prognosis is guarded and much similar to that of splenic hemangiosarcoma.
This disease process is often found suddenly and traumatically, as hemoabdomen is a common presenting sign. Knowing the statistics and the diagnostics may help clients make decisions about whether surgery is a good choice for their pet and their families.