Midgut carcinoids developing in the small intestine represent the most common cause of the carcinoid syndrome, with severe symptoms of flush, diarrhoea, and fibrotic valvular heart disease. The tumours may be histologically identified with specific chromogranin A or synaptophysine immunostainings, and by serotonin reactivity, which supports a midgut origin. Urinary 5-HIAA excretion and serum chromogranin A measurements are used as biochemical tumour markers for clinical diagnosis, and as important monitors of treatment effects and prognostic predictors. The midgut carcinoids have typically slow proliferation and extended disease course, and surgical treatment has become increasingly important for their management. Surgery should aim to remove primary tumours and mesenteric metastases, which may cause long-term abdominal complications, by typical fibrotic intestinal entrapment and small bowel ischaemia due to encasement of mesenteric vessels. Attempts should also be made to surgically remove or ablate liver metastases, since this may significantly contribute to palliation of the carcinoid syndrome. In patients with this syndrome surgery is combined with continuous biotherapy with long-acting somatostatin analogues and interferon, which may alleviate symptoms and cause stable disease with slow progression. Favourable survival and life-quality can be expected with this treatment also in patients with advanced midgut carcinoids.
(c) 2005 Wiley-Liss, Inc.