Paraneoplastic syndromes: the way to an early diagnosis of lung cancer.

Pulmonary malignancies are the leading cause of cancer mortality around the world. The late diagnosis of lung cancer, in advanced stages, is mainly due to atypical clinical presentation. Paraneoplastic syndromes have been first described in 1825, as a group of symptoms related to a malignant disease, which are not the effect of the primary neither of the metastatic tumor. The paraneoplastic syndromes have been reported in all types of lung cancer, but more frequently in small cell lung cancer, due to its origin in neuroendocrine cell precursors. The most frequent associated syndromes described in the literature are neurological and endocrine. In most patients paraneoplastic syndromes occur prior to other symptoms of malignancy. The presence or the severity of these syndromes is not correlated with the stage of cancer. Most of the paraneoplastic syndromes disappear once the primary tumor is removed and reappear in case of cancer recurrence or metastasis. This paper is a review of paraneoplastic syndromes in lung cancer.