Malignancy and Rheumatic Disease.

BACKGROUND: A wide variety of clinically significant interactions occur between neoplastic and rheumatic diseases, and many are clinically significant. METHODS: The types of interactions between rheumatologic and neoplastic diseases and their clinical manifestations are reviewed and described. RESULTS: Several diseases included in the classic definition of rheumatology are associated with an increased incidence of specific neoplasms. Conversely, many neoplasms, by a variety of mechanisms, can cause or simulate many rheumatic diseases. CONCLUSIONS: Knowledge of the increased propensity for neoplasia in certain conditions and of the possibility that cancer may be the cause of specific rheumatologic syndromes will assist the physician in providing optimal clinical care to affected patients.