Biology and management of the midgut carcinoid.

Midgut carcinoid tumors derive from gut entoderm. These tumors may cause a complex of symptoms comprising the carcinoid syndrome by secreting a wide variety of bioactive agents in addition to serotonin. Such symptoms generally follow metastases to the liver but may also occur in primary ovarian or retroperitoneal tumors. After localization and biochemical characterization, the bioactivity of these tumors should be blocked by octreotide, sometimes in combination with other pharmacologic antagonists, so that primary resection may be performed safely. If curative resection is impossible, then a cytoreductive management scheme should be employed that includes surgical debulking and hepatic arterial embolization, followed by palliation with octreotide.