Background: Leukemic synovitis is a rare complication of adult myeloid leukemias characterized by joint pain and swelling. It is important to recognize this diagnostic challenge as it may be the initial manifestation of leukemia or of relapse.
Methods: A retrospective search of patient files from 2 teaching hospitals identified 4 adult patients who presented with large joint arthritis and concurrent or subsequent leukemic synovitis. All patients presented with inflammatory arthritis of large joints, and leukemic synovitis was identified by the presence of leukemic cells in the synovial fluid or infiltrating the synovial membrane seen at biopsy.
Results: A leukemia of monocytic origin-acute myelomonocytic leukemia or chronic myelomonocytic leukemia-was diagnosed in all 4 patients. In 2 cases, leukemic synovitis was the initial manifestation of leukemia. In the third case, it was the first sign of relapse, and in the remaining case, it developed shortly after diagnosis of leukemia. All patients had either osteoarthritis or rheumatoid arthritis. One patient was diagnosed simultaneously with osteoarthritis and leukemia. The remaining patients had a prior history of arthritis.
Conclusions: Adult leukemic synovitis occurs in association with leukemias of monocytic differentiation. Data presented here, and review of isolated case reports, support this association. The finding of large joint arthritis as a comorbidity in these 4 cases raises questions about the role of antecedent arthritis as a predisposing factor in the pathophysiology of leukemic synovitis.