Paraneoplastic syndromes related to neuroendorine tumours

Low or high grade malignant neoplasms present syndromes secondary to symptoms related to local mass effects to surrounding structures or through the development of metastases. A significant number of neoplasms, irrespective of their endocrine differentiation, can present with clinical syndromes produced from the secretion of bioactive substances from tumoural cells, although this is more prevalent in neuroendocrine tumours. Occasionally syndromes related to the immune cross-reactivity of tumoural antigens with the normal tissues may also develop. These syndromes are named endocrine paraneoplastic when the specific secretory components (hormones, peptides or cytokines) are unrelated to the anticipated tissue or organ of origin. Endocrine paraneoplastic syndromes can precede, occur concomitantly or present at a later stage of tumour development and may complicate the patient’s clinical course, response to treatment, and impact overall prognosis. Their detection can facilitate the diagnosis of the underlying neoplasia, monitor response to treatment, detect early recurrences and correlate with prognosis. Although when associated with tumours of low malignant potential they usually do not affect long-term outcome, in cases of highly malignant tumours, endocrine paraneoplastic syndromes are usually associated with poorer survival outcomes. Currently, no specific underlying pathogenic mechanism has been identified although a number of plausible hypotheses have been put forward. However, advances in the localization and treatment of these syndromes have evolved and aim at early identification particularly as the number of these syndromes is expected to rise. The development of well-designed prospective multicentre trials remains a priority in the field in order to fully characterise these syndromes and provide evidence-based diagnostic and therapeutic protocols. For extended coverage of this and related topics, please see our FREE on-line web- text www.endotext.org