Approach to hepatic involvement by endocrine tumors of the gastrointestinal tract

Endocrine cells of the GI tract derive from stem cells of the neurocrest. They belong to the diffuse endocrine system as defined by Feyrter and share common features, such as the capacity for APUD cells. From these regulatory peptide-producing cells, endocrine tumors may develop with specific clinical symptoms. In some other endocrine GI tumors, no hormone secretion has yet been found, and for some regulatory peptides, no specific clinical entity has yet been identified. Diagnosis can be confirmed by hormone measurements and by specific immunohistochemistry or electron microscopy of the tumor tissue. Metastases synthesize and secrete peptide hormones like those of the primary tumors. The principal target organ for metastases is the liver. Several approaches to treatment of hepatic tumor deposits may reduce tumor mass with consequent reduction of effective plasma hormone levels. There are also systemic treatments for neuroendocrine tumors from the GEP system.