What Causes Hemangiosarcoma of the Spleen in Dogs?

Visceral hemangiosarcoma is the most serious of the varieties of hemangiosarcoma found in dogs and affects the spleen or heart. Hemangiosarcoma is an aggressive and malignant tumor of blood vessel cells that can also occur in the liver, skin and bones.

  1. Symptoms

    • Hemangiosarcoma tumors that develop in internal organs often show no symptoms until they rupture and, because they are blood-filled, cause serious internal bleeding. Symptoms that do occur include visible bleeding such as nose bleeds, lack of energy, difficulty breathing, seizures, collapse and depression. Additionally, the dog's gums may be pale or white.

    Causes

    • While the dermal form of hemangiosarcoma is considered a skin cancer and associated with exposure to the sun, internal hemangiosarcoma tumors seem to have few identifiable causes. However, according to caninecancer.com, research in humans on a similar type of cancer indicates a link to chemicals such as vinyl chloride.

    Dogs at Risk

    • Hemangiosarcoma tumors are more common in dogs than any other animal species. They usually occur in dogs older than 6 years and primarily in mid- to large-sized breeds.

    Treatment

    • Surgery is often indicated to remove the tumors and is usually accompanied by either chemotherapy or radiation.

    Prognosis

    • Prognosis varies depending on the development of the tumor at the time of diagnosis. The tumor is usually not detected until it has ruptured. If the spleen has ruptured, the prognosis is poor with, according to caninecancer.com, fewer than 10 percent of dogs surviving more than one year.