Intravascular lymphoma presenting with destructive rhinitis in a dog with epistaxis

Abstract Intravascular lymphoma is a rare form of lymphoma characterised by the proliferation of neoplastic lymphocytes within blood vessels, with a reported predilection for the central nervous system in dogs. An 8.5‐year‐old, female, spayed labrador retriever presented with a 3‐week history of intermittent sneezing and bilateral epistaxis. Computed tomography identified bilateral nasal turbinate lysis and an ill‐defined hyperattenuating left forebrain mass. Rhinoscopy confirmed the intranasal changes, and nasal mucosal biopsies were obtained. Severe epistaxis unresponsive to administration of tranexamic acid was observed post‐rhinoscopy, followed by cardiorespiratory arrest secondary to blood aspiration; resuscitation was declined. Fungal culture of the intranasal biopsies was negative. Histopathological analysis and immunohistochemistry performed on the nasal mucosal biopsies revealed a null‐cell, proliferating large cell lymphoma within the nasal blood vessels, indicative of intravascular lymphoma. This report describes the first case of intravascular lymphoma manifesting with destructive rhinitis in a dog.