Carcinoid syndrome and neuroendocrine tumours

Neuroendocrine neoplasms (NENs) are relatively rare tumours arising from neuroendocrine cells, commonly in the gastrointestinal tract, with small intestine NENs (SI-NENs) being the most frequent primary site. SI-NENs frequently metastasize to the liver and approximately 30% of patients present with carcinoid syndrome. Imaging of SI-NENs typically reveals mesenteric fibrosis around a mesenteric mass. The diagnosis is confirmed by histology. Functional imaging (e.g. ⁶⁸Ga-DOTA-somatostatin analogue positron emission tomography/computed tomography) is important for tumour staging. Management requires a multidisciplinary approach. General treatment principles include therapies aimed at symptom control versus disease modification, including surgery (with curative or debulking intent), as well as targeted or systemic therapy.