Carcinoid Tumorlets Co-Existing with Chronic Pulmonary Inflammatory Processes: Imaging Findings and Histological Appearances

BACKGROUND: Pulmonary carcinoid tumorlets (PCT) are incidental histologic or radiologic discoveries that are localized neuroendocrine tumors whose proliferation is associated with chronic pulmonary inflammatory processes. This study assessed the imaging findings and histological appearances of PCT co-existing with chronic pulmonary inflammatory processes. MATERIAL/METHODS: We performed a retrospective study of 14 patients with incidentally-found PCT with co-existing chronic pulmonary inflammatory processes who underwent preoperative X-rays and CT between 1 January 2003 and 31 December 2012. The clinical symptoms, X-rays, CT imaging findings, and histological appearances were retrospectively evaluated. RESULTS: Twelve women and 2 men were found to have PCT, with a mean age of 55.29±13.90 years (range 25–74 years) at diagnosis. Among these 14 patients, hemoptysis, cough, chest pain, expectoration, and chest tightness were found in 9 (64.3%), 5 (35.7%), 4 (28.6%), 3 (21.4%), and 1, respectively. For most patients, we could not find any small nodules on the X-ray or CT images. However, indirect imaging findings of bronchiectasis (85.7%, 12/14), atelectasis (57.1%, 8/14), inflammation (92.8%, 13/14), tuberculosis (7.1%, 1/14), and lung cancer (7.1%, 1/14) were found in all 14 patients. CONCLUSIONS: PCT occurs most commonly in middle-aged women who have chronic pulmonary inflammatory processes such as bronchiectasis, atelectasis, and inflammation. Although there are no specific symptoms or direct imaging findings in these patients, our results showed that patients who have bronchiectasis, atelectasis, or recurrent pulmonary infection are at increased risk for PCT.