Wednesday, July 11, 2007

Bronchial Carcinoid

Bronchial carcinoids are rare, slow-growing neuroendocrine tumors arising from bronchial mucosa that affect patients in their 40s to 60s.

Half of patients are asymptomatic, and 1⁄2 present with symptoms of airway obstruction, including dyspnea, wheezing, and cough, which often leads to a misdiagnosis of asthma. Recurrent pneumonia, hemoptysis, and chest pain are also common. Paraneoplastic syndromes, including Cushing's syndrome due to ectopic ACTH, acromegaly due to ectopic growth hormone–releasing factor, and Zollinger-Ellison due to ectopic gastrin production, are more common than carcinoid syndrome (see Carcinoid Tumors: Carcinoid Syndrome), which occurs in < 3% of patients with the tumor. A left-sided heart murmur (mitral stenosis or regurgitation) occurs rarely due to serotonin-induced valvular damage (as opposed to the right-sided valvular lesions of GI carcinoid).

Diagnosis is based on bronchoscopic biopsy, but evaluation often initially involves chest CT, which reveals tumor calcifications in up to 1⁄3 of patients.

Drug Information
scans are useful for determining regional and metastatic spread. Increased urinary serotonin and 5-hydroxyindoleacetic acid levels support the diagnosis but are not commonly present.

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