Abstract
Paraneoplastic disorders is a group of hetrogenous diseses/syndromes. A paraneoplastic syndrome is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells.
These phenomena are mediated by humoral factors (by hormones or cytokines) excreted by tumor cells or by an immune response against the tumor. Paraneoplastic syndromes are typical among middle aged to older patients, and they most commonly present with cancers of the lung, breast, ovaries or lymphatic system (a lymphoma).
Sometimes the symptoms of paraneoplastic syndromes show before the diagnosis of amalignancy, which has been hypothesized to relate to the disease pathogenesis. In this paradigm, tumor cells express tissue-restricted antigens (such as neuronal proteins), triggering an anti-tumor immune response which may be partially or, rarely, completely effective in suppressing tumor growth and symptoms.
Patients then come to clinical attention when this tumor immune response breaks immune tolerance and begins to attack the normal tissue expressing that (e.g. neuronal) protein. There are reviewed the most common paraneoplastic disorders in the article.