Resolution of reactive arthritis after splenectomy in a dog with a nonneoplastic splenic hyperplastic nodule.

Case Description: A 10-year-old spayed female Golden Retriever was examined because of a 3-month history of lethargy, anorexia, and stumbling gait.

Clinical Findings: A splenic mass was identified on abdominal radiography and ultrasonography, and results of clinicopathologic findings indicated nonregenerative anemia, leukocytosis, and high serum C-reactive protein (CRP) concentration. To further investigate the cause of the dog's high serum CRP concentration, radiography and arthrocentesis were performed bilaterally on the carpal and stifle joints. On the basis of results, anemia of chronic disease associated with polyarthritis caused by the localized splenic mass was suspected.

Treatment And Outcome: After splenectomy, there were improvements in the dog's clinical signs, polyarthritis, nonregenerative anemia, and serum CRP concentration. The splenic mass was histologically diagnosed as a nonneoplastic splenic hyperplastic nodule with evidence of omental adhesion.

Clinical Relevance: Findings indicated that nonneoplastic splenic hyperplastic nodules could result in reactive polyarthritis, although such nodules have not to our knowledge been described previously as an underlying cause of polyarthritis. Therefore, veterinarians should investigate for nonneoplastic splenic hyperplastic nodules in addition to other typical underlying causes when treating dogs with polyarthritis.