Haemangiosarcoma

Introduction

A highly malignant tumour of vascular endothelial origin. Commonly affect dogs and the most frequently affected areas are the spleen, pericardium, right atrium, liver and muscle. The cat is affected less frequently and the most common sites are the liver, spleen and mesentry. Metastasis occurs via the haematogenous route or via rupture and transabdominal spread. Metastatic sites include, lungs, liver, omentum, diaphragm and less commonly brain. Surgery is the treatment of choice but even with this survival time remains very short.

Signalment

Often found in German Shepherd Dogs and Golden Retrievers over 9 years of age. Domestic Short haired cats are the most commonly affected cat breed.

History and Clinical Signs

Can vary depending on the anatomic site that the mass is affecting. Signs such as anorexia, lethargy, weakness, vomiting and anaemia are common. Animals may have history of multiple episodes of collapse following repeated rupture of an abdominal mass, leading to non-fatal haemoabdomen. Occasionally can be found dead following catastrophic rupture and fatal haemoabdmen.

In instances where the heart (right auricle) is involved, animals may die suddenly or present in heart failure. Rupture of the mass and haemorrhage into the pericardial sac leads to compression of the heart, which can no longer fill with blood during diastole (cardiac tamponade).

If the nervous system is involved a range of neurological abnormalities will also be present.

Laboratory Tests

Haematology

Anaemia will be evident which may be regenerative if due to blood loss, or microangiopathic due to the passage of red blood cells through the microvascular network of the tumour. This results in the presence of schistocytes in dogs but not cats. A neutrophilia and thrombocytopenia may also be present.

Diagnostic Imaging

Radiography

Useful to look for evidence of metastasis.

Ultrasonography

This is sensitive in identifying liver and splenic masses where the spleen will show a mixed or non-homogenoeous pattern and the liver will look hypoechoic or anechoic. It can also be useful to detect metastatic spread.

Biopsy

The only way to to form a definitive diagnosis is following a biopsy and histopathology. This is needed to differentiate haemangiosarcoma from splenic haematoma, haemangioma and accessory splenic tissue.

Treatment

Surgery

Surgery is the treatment of choice for haemangiosarcoma in the dog and cat. All diseased tissue should be removed and splenic haemangiosarcoma should be treated via splenectomy. Local removal is difficult if the pericardium and right atrium is involved. A pericardectomy can be undertaken but the prognosis with tumours at this location is grave.

Chemotherapy

This will provide a palliative treatment for animals with multiple masses or as an adjuvant therapy post-operatively. Doxorubicin based products are the most commonly used drugs for haemangiosarcomas.

Prognosis

Poor due to high risk of metastasis in the early course of the disease.

{{Learning |flashcards = Liver Pathology Flashcards |literature search = Haemangiosarcoma |full text = A review and what's new in canine hemangiosarcoma. Garrett, L. D.; The North American Veterinary Conference, Gainesville, USA, Small animal and exotics. Proceedings of the North American Veterinary Conference, Orlando, Florida, USA, 16-20 January 2010, 2010, pp 956-959

References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company.

Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition) BSAVA

Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.