A few cancer patients can present with arthritis and other rheumatologic diseases such as vasculitis, myositis, and metabolic bone disease. Underlying malignancy is usually suspected in patients with explosive onset of atypical arthritis, especially at an older age. This arthritis usually does not respond to standard antirheumatic therapy.
The malignancy may be occult, although a search for such occult malignancy is not cost-effective.
Early diagnosis of malignancy is possible with a correct diagnosis of cancer-associated syndromes. Some of the musculoskeletal symptoms resolve with successful treatment and relapse with recurrence of malignancy.
Common cancers causing musculoskeletal syndromes include leukemia, multiple myeloma, and cancers of ovaries, bowel, lungs, and liver.
Patients on drugs such as cyclophosphamide and biologic agents have an increased risk of cancer. There is an increased risk of cancer in patients with rheumatoid arthritis and Sjögren's syndrome.