Abstract
BACKGROUND: Malignant fibrous histiocytoma has been uncommonly described in dogs. Several extranasal neoplasias have been reported to result hypertensive epistaxis. There are, however, no published case reports of extranasal malignant fibrous histiocytoma with concurrent hypertension and epistaxis in dogs. CASE PRESENTATION: A 10-year-old dog presented with a spontaneous massive epistaxis persisting for 5 days. The dog exhibited unstable hypertension, which was considered as a cause of epistaxis. The complete blood count, prothrombin time, and activated partial thromboplastin time were within the reference limits, and other systemic examination showed no abnormalities except for a splenic mass occupying more than one third of the abdomen. Histologic examination of the resected spleen revealed the characteristic features of a malignant fibrous histiocytoma. One week after splenectomy, the hypertension and epistaxis resolved clinically and did not recur on the 5-month follow-up. CONCLUSIONS: The dog's blood pressure and epistaxis normalized after malignant fibrous histiocytoma resection suggesting that hypertensive epistaxis may be a rare manifestation of canine malignant fibrous histiocytoma.