Malignant Metastatic Plasma Cell Tumor in a Dog

A primary metastatic malignant plasma cell tumor was diagnosed in a 7-year-old, female mixed breed dog. The dog was admitted to Veterinary Teaching Hospital at College of Veterinary Medicine, Seoul National University after suffering from depression, anorexia, and dyspnea. In radiographic examination, a large occupying mass was found at the right cranial thorax. Due to poor prognosis, the dog was euthanized. At surgery, numerous, firm, round, nodules, 1 to 2 cm in diameter were noted in the ribs. The nodules were often confluent and had cylindrical appearance. Osteolysis was associated with the nodules. A large amount of clear fluid was present in the thoracic cavity. The spleen and liver were markedly enlarged and congested. Histologically, the mass was diagnosed as plasma cell tumor which was believed to be originate from the rib. Evidence of metastasis was observed in the spleen, liver, and kidney.