A Clinicopathological Study Of Mucoepidermoid Carcinoma Of The Lung In Surgical Cases

BACKGROUND: Mucoepidermoid carcinoma (MEC) of the lung, which is relatively rare, has been regarded as having low-grade malignant potential. however, we often encounter cases with advanced MEC showing local invasion or distant metastasis. here, we assessed the clinicopathological characteristics of MEC in patients undergoing surgery.METHODS: Of 1534 lung cancer patients who underwent surgical treatment at our hospital and the associated institutes between 1990 and 2014, we enrolled 11 patients (7 men and 4 women with a mean age of 59.7 years [42-93 years]) with histologically confirmed diagnosis of MEC (0.72%). Pathological staging was IA in 2, IB in 1, IIA in 1, IIIA in 5, and IV in 2 patients. The primary tumor was classified, according to tumor localization, as central type in 6 or peripheral type in 5 patients. Operative methods included pneumonectomy in 3, lobectomy in 4, wedge resection in 2, and tracheal (or bronchial) sleeve resection in 2 patients. The histological grade was I in 5, II in 4, and III in 2 patients.RESULTS: None of the patients were preoperatively diagnosed with MEC. according to the TMN staging, the 10-year survival rate for those with N0M0 was 100%, whereas the 3-year survival rate for those with N(+) or M(+) was 0%. according to primary tumor location, the 10-year survival rate for the central type was 66.7%, whereas the 4-year survival rate for the peripheral type was 30%. according to histological grade, the 10-year survival for grade 1 was 80% and the 4-year survival rate for grade 2 and 3 was 22%. The 10-year survival rate for female patients was 100%, whereas the 9-year survival rate for male patients was 19%. Patients with long-term survival all had a grade 1 central type tumor.CONCLUSIONS: To optimize MEC treatment, the accuracy of preoperative diagnosis needs to be improved. Patients diagnosed with low-grade MEC should undergo lung function-preserving surgery if possible. Meanwhile, adjuvant therapy for high-grade MEC is a challenging issue.