[Paraneoplastic syndromes (1)].

Although not rare, paraneoplastic syndromes develop in a minority of cancer patients. Their exact frequency seems to be underestimated. These syndromes are hereby described. Their clinical usefulness is of great importance: they can be the first sign of a malignancy and can be used as tumor markers. The diagnosis of paraneoplastic syndromes is often difficult. A "diagnosis score" is proposed in order to make the diagnosis easier.