Histiocytic Sarcoma in Dogs

Histiocytic sarcoma in dogs is an aggressive form of cancer that’s generally fatal. Breeds that are susceptible to this disease include Bernese Mountain Dogs, Flat Coated Retrievers, Doberman Pinschers, Golden Retrievers, Labrador Retrievers and Rottweilers. The sarcoma is caused by congenital factors and affects cells of the immune system known as histiocytes.

Histiocytes and Their Effect

Histiocytes are leukocytes or white blood cells that are tissue based. They are differentiated tissue cells that originate in the bone marrow and develop into macrophages when they migrate to tissue cells. These monocytes are phagocytic in nature. Since they ingest other cells, they play an important role in the proper functioning of the immune system.

Canine Histiocytic Sarcoma

Histiocytic sarcomas occur in organs such as the spleen, the lymph nodes, the lungs, the bone marrow and the skin. These sarcomas are cancerous in nature and are soft tissue tumors that arise from histiocytes. There are 2 types of histiocytic sarcomas namely localized and disseminated. Localized histiocytic sarcomas are limited to a single site and are moderately aggressive.

They have the capacity to metastasize to distant organs. They occur on or under the skin of the pet’s limbs, in the spleen, the lung and the periarticular tissue. Disseminated histiocytic sarcomas are malignant cancers that are widespread and occur in several organs such as the lungs, the spleen, the lymph nodes, the bone marrow and the liver.

Symptoms of Histiocytic Sarcoma in Dogs:

  • Loss of appetite
  • Loss of weight
  • Lethargy
  • Weakness
  • Prominent eyeballs
  • Recurrent fevers
  • Enlarged lymph nodes
  • Anemia 
  • Decrease in platelet count

Diagnosis of Canine Histiocytic Sarcoma

An evaluation of the pet’s medical history, a physical exam and tests like X-rays, biopsy or aspiration of the regional lymph nodes, bone marrow cytology and an abdominal ultrasound can help the vet confirm the diagnosis.

Treatment of Histiocytic Sarcoma in Dogs

Treatment of localized histiocytic sarcoma involves the surgical removal of the tumor. Radiation can help kill remaining cancer cells that have not been removed by surgery.

Treatment of disseminated histiocytic sarcoma is not very successful and involves chemotherapy. Surgery and radiation are not treatment options in cases of disseminated histiocytic surgery. Medications to manage pain should be administered in order to decrease your pet’s discomfort.

Prognosis of Histiocytic Sarcoma in Dogs

This disease is rapidly progressive in nature. The prognosis for pets with localized histiocytic sarcoma is good if the tumor is on or under the skin and is completely removed surgically before it has a chance to metastasize. If the tumor is in an organ such as the spleen, the prognosis is poor.

A pet may survive for a month and only 20 percent of affected pets survive for a year after the onset of the disease. In cases of disseminated histiocytic sarcoma, prognosis is very poor. Very few pets survive for 4 months and none for a year after the onset of the disease.

A qualified veterinary oncologist can help your pet in his fight with this malignant form of cancer. Proper nutrition is especially essential in order to maintain your pet’s strength and help him respond to therapy. Good care can improve survival time and enhance the healing process.