Clinicopathological and multisection CT features of primary pulmonary mucoepidermoid carcinoma

Aim: To delineate the multisection computed tomography (MSCT) features and the clinical characteristics of primary pulmonary mucoepidermoid carcinoma (PMEC). Prognostic factors were also analysed.

Materials and methods: A retrospective study was undertaken to investigate the medical records and MSCT performance of histopathologically confirmed PMECs from 2007 to 2015.

Results: A total of 83.3% of patients with high-grade PMECs were aged >40 years, whereas there were 1.5-times more women than men with low-grade PMECs. Cough (n=29) and haemoptysis (n=12) were the most common symptoms. Upon MSCT, 30 cases showed a round or lobulate mass, and few demonstrated bronchial-wall thickening or cavities. Distal obstruction (n=14) and "air crescent sign" (n=5) could be detected. Tumours showed mild (n=19), moderate (n=5), and marked enhancement (n=5). Moreover, 18 cases showed foci of low density in lesions. Mean survival for patients with low-grade PMECs was 59.2 months, whereas that for high-grade PMECs was 20.4 months; 3-year survival rates were 55% and 14%, respectively. Tumour staging was a significant independent predictor of survival according to the Cox proportional hazards model.

Conclusion: High-grade PMECs occurred more frequently in patients aged >40 years and were more predominant in men. Young females were predisposed to having low-grade PMECs. MSCT revealed an oval or lobulate mass with mild enhancement, as manifested by calcification and visible mucus lakes, which may be suggestive of PMECs. Furthermore, a central nodule or mass may suggest low-grade PMECs; high-grade PMECs tend to be peripheral and associated with lymph-node metastasis. Pathological grade, lymph node metastasis, and TNM stage correlate with the survival of patients with PMEC.