Links between rheumatic manifestations and neoplasms are today an evidence. Certain syndromes have epidemiologic studies confirming strong association with malignancy, such as dermatomyositis and polymyositis, hyperthrophic osteoarthropathy and Lambert - Eaton myasthenic syndrome. These disorders may mimic idiopathic conditions, difficulting diagnosis. Besides that, longstanding rheumatic syndromes may, in their course, behave like premalignant conditions, as a result of their pathophysiology or drugs used in their treatment. The mechanisms whereby the neoplasm leads to rheumatic symptoms are: direct invasion of the musculoskeletal system, synovial reaction of justa-articular bony or capsular carcinomatous, secondary gout and paraneoplastic manifestations. Neoplasms constitute an important admission cause in Internal Medicine wards and rheumatic manifestations are common causes of Internal Medicine and Rheumatology appointments. The objective of the present work is to review the literature concerning rheumatic syndromes more frequently associated with malignancy, characterizing features that may suggest the presence of a hidden neoplasm as well as the potential diagnostic and prognostic value of their presence in malignant diseases.