What are pulmonary carcinoid tumors?
These are rare neuroendocrine neoplasms that range from low-grade typical carcinoids to more aggressive atypical carcinoids. They are not related to tobacco use and occur slightly more commonly in women. Most arise centrally in an endobronchial location and are commonly associated with segmental or lobar obstructive atelectasis or pneumonitis, whereas the remainder appear as well-circumscribed peripheral pulmonary nodules or masses. These lesions typically show avid enhancement, and 40% may be associated with internal calcification. Carcinoid syndrome is rarely associated with pulmonary carcinoid tumors.