T cell ALL presenting as seropositive rheumatoid arthritis: case report and review of the literature on seropositive paraneoplastic arthritis.

We present the case of a 61-year-old female with an acute onset of polyarthritis involving the wrists, hands, knees, and ankles. Associated systemic symptoms included fever, weight loss, and lymphadenopathy. Serologic workup revealed positive rheumatoid factor (RF) and anti-cyclic citrullinated protein (anti-CCP) antibodies. Radiograph imaging of her bilateral hands and wrists showed erosive joint disease and lymph node, and bone marrow biopsy confirmed a diagnosis of T cell lymphoblastic leukemia. Our case demonstrates a unique clinical phenotype of paraneoplastic arthritis and is only the second reported case of RF, anti-CCP-positive arthritis related to a hematological malignancy. We review the only three published cases of seropositive paraneoplastic arthritis. In each case, systemic symptoms or a poor response to steroid treatment triggered additional workup. These cases highlight the importance of careful clinical assessment and vigilance to rule out secondary causes of inflammatory arthritis, even in patients with seropositive erosive arthritis.