Haemangiosarcoma
From Felipedia
Hemangiosarcoma (HSA), unlike their benign counterpart, the haemangioma, are malignant neoplasm arising from vascular endothelial cells. They may appear peripherally as cutaneous haemangiosarcoma or as systemic hemangiosarcoma.
These tumours are uncommon in cats, with a reported incidence of 0.3% to 2.0% (Withrow et al, 2001). Although the visceral form of HSA is the most common, primary cutaneous HSA has also been reported and accounted for 1.8% of all cutaneous tumours in one study of 340 cats. Previous studies suggest that the most common primary sites for cutaneous HSA in the cat are the pinna, lateral face, and inguinal or abdominal subcutis.
There appears to be no sex or breed predilection for hemangiosarcoma. Many cats appear to develop metastases and complications associated with multi-organ tumour involvement despite surgical intervention in many cases. It is uncommon to assign a histological grade to HSA, but it is plausible that some tumours are inherently more aggressive (i.e., high grade) than others and in many studies, a higher proportion of low-grade lesions respond favourably to surgical excision.
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Clinical signs
Lymphocytic infiltrates are associated with longer survival times in humans with cutaneous HSA. Tumours occur commonly in the subcutaneous regions of the trunk or proximal pelvic limbs, subcutaneous regions of the head and tips of the ears. Numerous studies in dogs and humans have also documented that the cutaneous form of HSA tends to occur in non-haired, non-pigmented skin. Potential predisposing factors for cutaneous HSA in humans are vascular stasis, previous radiation therapy, trauma, and sun exposure. Solar radiation has been proposed as a cause of cutaneous HSA in dogs, and cutaneous HSA has also been experimentally induced using ultraviolet radiation in dogs, however it is thought that in cats, that ultraviolet radiation and/or solar exposure were not causative factors in the disease.
Histopathology
Common findings on histopathological examination include broad sheets of large numbers of polygonal to round cells with abundant eosinophilic cytoplasm that occasionally form blood filled channels. Nuclei are often polygonal with dispersed chromatin and single eosinophilic nucleoli. Usually there are large multifocal to coalescing areas of necrosis in the spleen with numerous accumulations of intracellular and extracellular hemosiderin. Many neoplastic cells contain large intracytoplasmic lipid vacuoles. There are occasional multinucleated giant cells, with around 35-40 mitotic figures in 10 random 400x fields. There is moderate anisocytosis and anisokaryosis with occasional bizarre mitotic figures and individual cell necrosis. There is mild extramedullary hematopoiesis.
Treatment
Surgery is the primary method of treatment for feline hemangiosarcomas. Tumour location at the time of surgery does not appear to statistically affect median survival time in cats post-operatively. In a study by Ward et al in dogs with cutaneous HSA, surgical excision of superficial dermal HSA resulted in a median survival time of 780 days, whereas median survival times for subcuticular lesions were <1 year. Cats with tumours located in the subcutaneous tissues and those with muscle involvement appear to have the longest survival time. Previous studies in humans have indicated that tumor size was prognostic in cutaneous HSA, with tumours <5 cm in diameter having significantly longer survival times, but in cats there does not appear to be a statistically significant relationship between tumour size and median survival time. Complete or partial surgical excision of cutaneous HSA in cats resulted in long survival times (mean survival time 622 days, range 90 to 1460 days) regardless of age, tumor size, or tumor location. The median survival time was 60 days for unoperated cats, indicating that aggressive surgical excision of cutaneous HSA provided a better long-term prognosis than previously reported.
Chemotherapy has resulted in prolonged survival in dogs with cutaneous HSA11. Vincristine, doxorubicin, and cyclophosphamide have been used in combination with cutaneous HSA, with median survival times of 425 days.
References
1. Withrow SJ, MacEwen EG. Small Animal Clinical Oncology. 3rd ed. Philadelphia: WB Saunders, 2001:639–640.
2. Prymak C, McKee LJ, Goldschmidt MH, et al (1988). Epidemiologic, clinical, pathologic, and prognostic characteristics of splenic hemangiosarcoma and splenic hematoma in dogs: 217 cases. J Am Vet Med Assoc193:706–712
3. McAbee, KP, et al. (2005). Feline Cutaneous Hemangiosarcoma: A Retrospective Study of 18 Cases (1998–2003). Journal of the American Animal Hospital Association 41:110-116 (2005)
4. Miller MA, Nelson SL, Turk JR, et al (1991). Cutaneous neoplasia in 340 cats. Vet Pathol 28:389–395.
5. Miller MA, Ramos JA, Kreeger JM. Cutaneous vascular neoplasia in 15 cats: clinical, morphologic, and immunohistochemical studies. Vet Pathol 1992;29:329–336
6. Scavelli TD, Patnaik AK, Mehlhaff CJ, et al (1985). Hemangiosarcoma in the cat: retrospective evaluation of 31 surgical cases. J Am Vet Med Assoc 187:817–819
7. Jan NA, Anderson T, Siegel R (1990). Angiosarcoma of the forearm definitively treated by hyperfractionated irradiation. Am J Clin Oncol 6:489–494.
8. Ward H, Fox LE, Calderwood-Mays MB, et aln (1994). Cutaneous hemangiosarcoma in 25 dogs: a retrospective study. J Vet Intern Med 8:345–348
9. Liu AC, Kapp DS, Egbert B (1990). Angiosarcoma of the face and scalp. Ann Plast Surg 24:68–74.
10. Wolf K, Pasquino J (1990). Cutaneous angiosarcoma. J Am Podiatr Med Assoc 9:501–504.
11. Hammer AS, Couto CG, Filppi J, et al (1991). Efficacy and toxicity of VAC chemotherapy (vincristine, doxorubicin, and cyclophosphamide) in dogs with hemangiosarcoma. J Vet Intern Med 5:160–166.
