Angiofibroma of the Nasal Cavity in a Dog: Case Report.

Nasopharyngeal angiofibroma is a histologic benign but locally aggressive vascular tumor described in humans. The description of this disease in dogs is limited. A mixed-breed female dog was presented with a history of epistaxis and nasal discharge. Rhinoscopy and computed tomography revealed a soft-tissue mass obstructing the entire nasal cavity, choana, maxillary recess, and right frontal sinus, but there was no bone or lymph node involvement. Histopathologic evaluation revealed irregular groups of blood vessels within a stroma of connective tissue, with secondary inflammation. Immunohistochemistry showed strong vimentin staining, mild factor VIII-related antigen staining, and negative staining for S100. The patient underwent tumor resection with fenestration surgery through the right maxillary bone, and there was tumor recurrence one year after surgery. This case report describes new findings regarding the immunohistochemical evaluation of nasopharyngeal angiofibroma in a dog. The laboratory and imaging findings, associated with a long-term follow-up, reinforce similar features between human and canine angiofibroma and may serve as a basis for immunohistochemical evaluation of this tumor in dogs.