Bronchial and thymic carcinoid tumors: a review

Bronchial carcinoid tumors are usually indolent, slow-growing tumors with an excellent prognosis. However, even typical carcinoids can metastasize to regional lymph nodes or to distant sites. Atypical carcinoids tend to behave more invasively with more frequent nodal and distant metastases. Despite this, long-term survival can be expected as many tumors grow and spread slowly. At the end of the spectrum are the highly aggressive small cell carcinomas which have a very poor prognosis despite aggressive chemotherapy. Clinically, carcinoid tumors are frequently asymptomatic. Symptoms are most frequently due to obstruction (pneumonia, 'asthma', coughing) or bleeding. Carcinoid syndrome is seen infrequently and usually signifies metastatic disease. Cushing's syndrome is occasionally seen in association with these tumors. The treatment of carcinoid tumors is surgical. Resection should be complete and encompass the regional lymph nodes.