Carcinoid Tumour Case Study

Apr 15, 2013George Potamitis

George S. Potamitis*, Diana T. Vulcanescu, Christoforos Varianos, Panikos Nikolaou, Rebecca Anastasiadou, Theodoros Lysiotis.

INTRODUCTION

Carcinoid tumours originate in the cells of the neuroendocrine system.  They have been classified according to their embryologic site of origin, such that foregut carcinoids start in the lungs, bronchi or stomach; midgut carcinoids start in the small intestine, appendix, or proximal large bowel; and hindgut carcinoid tumors start in the distal colon or rectum.1  The appendix presents the most frequent site of carcinoid tumours followed by the rectum, ileum, lungs, bronchi, and stomach.2  These neoplasms characteristically present in patients 50 to 60 years of age.3

Carcinoid tumours contain many neurosecretory granules responsible for the synthesis, storage, and release of substances, including serotonin, histamine, prostaglandins, kallikrein, bradykinins, substance P, gastrin, corticotrophin (ACTH), and neuron-specific enolase. The most prominent of these substances is serotonin (5-hydroxytryptamine) which is degraded into 5-hydroxyindoleacetic acid (5-HIAA), which in turn is excreted in the urine.  Initially, the lungs and liver metabolize many of the substances secreted by carcinoid tumours, consequently preventing their release into the systemic circulation until metastases develop.5  When they are finally released into the systemic circulation, 5-hydroxytryptamine can elicit symptoms of the so-called carcinoid syndrome.6 This syndrome occurs in less than 10% of patients, and its most characteristic clinical manifestations include cutaneous flushing (face, neck, upper chest) and diarrhea.7

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