Diagnosis and Treatment of Malignant Carcinoid Syndrome

Abstract

THE malignant carcinoid syndrome has challenged the skills of the clinician, biochemist, and pharmacologist since its original description by Biorck et al 1 22 years ago. Although attention originally centered on a symptom complex and a serotonin-producing midintestinal neoplasm that had metastasized to the liver, the carcinoid syndrome has now been expanded to include a spectrum of biochemical, anatomic, and histologic variants. These embrace such diverse sites as stomach, rectum, bronchus, ovary, pancreas, biliary tract, and Meckel diverticulum, and are expressed biochemically by the tryptophan-serotonin pathway, histamine, the kinin-kallikrien system, and probably other vasoactive amines. 2 The malignant carcinoid syndrome has been associated with tumor production of immunoreactive insulin, secondary hypoglycemia, Cushing syndrome via corticotropin, and hyperpigmentation via melanotropin secretion. 3 In addition, the malignant carcinoid syndrome may present as a paraneoplastic syndrome of such noncarcinoid malignant neoplasms as oat cell cancer of the lung, medullary cancer of the thyroid,