Anticyclic citrullinated peptide antibody-positive paraneoplastic polyarthritis in a patient with metastatic pancreatic cancer.

Neoplasms may present as rheumatic disorders. Some of these rheumatologic manifestations may be paraneoplastic and can clinically and serologically mimic rheumatoid arthritis (RA). We report the case of a patient who initially presented with an asymmetrical, rapid onset polyarthritis. It resembled atypical RA with positive rheumatoid factor and anticyclic citrullinated peptide (CCP) antibodies. A good response to steroid therapy was noted. A few weeks later, he was diagnosed with metastatic pancreatic cancer that resulted in his mortality. His clinical course suggested that his rheumatic symptoms were a paraneoplastic manifestation of his underlying malignancy. Anticyclic citrullinated peptide antibodies have not been previously described in cancer polyarthritis. Awareness of this atypical, seropositive RA-like syndrome may prompt clinicians to investigate for an underlying malignancy.