Nasal extramedular plasmacytoma in a dog

A case of nasal plasmacytoma with history of chronic unilateral epistaxis in a twenty-one month old, male, Akita dog, weighing 30 kg is described. Clinical examination and biopsy of the visible tumor in the left nasal cavity were performed. The location and extent of the tumor were determined by head and neck computer tomography. Histopathological and immune-histochemical (IHC) analyses of tumoral tissue were performed. Computer tomography showed a mass with soft tissue density of 10 cm long x 3.5 cm in diameter and low uptake of the contrast medium that entirely compromised the right nasal cavity and part of the rear portion of the left choana. The histopathological analysis revealed the presence of numerous pleomorphic round cells with little cytoplasm, surrounded by a scarce network of connective tissue, and a low mitotic index. The IHC analysis was negative for CD3 and CD20 antigens or T and B lymphocytes, respectively. Clinical and computer tomography findings, such as the results of the histopathology of the tumoral tissue were consistent with a low-grade malignancy extramedular plasmacytoma.