Endocrine Abstracts

According to the WHO classification system the majority of endocrine tumours of the gastrointestinal tract (GI-NETs) are considered as being well differentiated benign or malignant tumours. Almost all GI-NETs are derived from enterochromaffin or Kulchitsky cells that can synthesize, store and secrete serotonin. The majority of these tumours are non-functioning and their presentation is non-specific. Functioning tumours, may exhibit protean clinical presentation, depending on the combination of bioactive substances (serotonin, tachykinins, kallikreins, prostaglandins among others) that they secrete. The typical ‘carcinoid syndrome’ occurs in less than 10% of patients and is clinically manifested as cutaneous flushing and gut hypermobility with diarrhoea. Cutaneous flushing of the face, neck and upper chest are characteristic features; less common manifestations include cardiac valvular abnormalities, abdominal pain, and bronchospasm. Symptoms can occur spontaneously or triggered by alcohol intake, serotonin-rich foods and exercise. Carcinoid crisis is an extreme and life threatening expression of the carcinoid syndrome occurring as a consequence of the massive release of amines into the circulation following anaesthesia, interventional procedures or medication. Hypotension, rarely hypertension, tachycardia, bronchial wheezing and central nervous system dysfunction are the main features. Rarely, an atypical carcinoid syndrome or syndromes related to other biologically active substances released by the tumours may occur and dominate the clinical picture. In the majority of patients the carcinoid syndrome can be treated with somatostatin analogues, interferon alpha or combinations. Severe carcinoid heart valve disease is treated with valve replacement. Additional therapies are surgery, surgical debulking, radiotherapy, liver dearterialization, liver (chemo- or radio) embolization, alcohol sclerotherapy of liver metastases, radiofrequency ablation of liver metastases, cryosurgery of liver metastases, occasionally liver transplantation, radiotherapy-coupled somatostatin analogues, 1312I-MIBG and occasionally chemotherapy.