Background: Pulmonary mucoepidermoid carcinoma is a rare tumor of the lung. The clinicopathological characteristics of pulmonary mucoepidermoid carcinoma are not well defined due to the low incidence. This study was performed to provide more supplementary clues for the identification and understanding of pulmonary mucoepidermoid carcinoma. Methods: We reviewed the medical records since January 1, 2000 to December 31, 2018. The patients’ medical records，including age at the time of diagnosis , gender, smoking history, preoperative evaluations, operative procedures, tumor location, tumor size, tumor stage, lymph node metastasis, pathological markers, prognosis and survival information were extracted and reviewed. Categorical variables were presented as parameters and percentages. A comparison was performed between patients with high and low grade of pulmonary mucoepidermoid carcinoma. Results: 20 patients were identified and the age span is from 18 to 67 year-old with the average age is 45. Mucoepidermoid carcinomas were commonly found in men（60%）. 80% patients had clinical presentations and the positive rate of tumor markers was 78%, although no specific tumor markers were found. TTF-1 were negative in all cases. ALK rearrangement was identified in a non-smoking woman with high grade pulmonary mucoepidermoid carcinoma. Surgery is the main procedure. 3-year survival rate is 72% and 80% patients achieved disease-free alive. High-grade patients tend to harbor older age (p=0.035), larger tumor volume (p=0.026) and higher index of ki-67(p=0.0005). Conclusions: Pulmonary mucoepidermoid carcinoma could occur in a wide age span. Early diagnosis and complete surgical resection may promise a good prognosis. Grading is a key factor to predict the overall survival time. Combined TTF-1 and MAML2 will benefit the identification of pulmonary mucoepidermoid carcinoma from other lung tumors. Future prospective randomized controlled trials and larger, multi-centric series are needed.

Background: Pulmonary mucoepidermoid carcinoma is a rare tumor of the lung. The clinicopathological characteristics of pulmonary mucoepidermoid carcinoma are not well defined due to the low incidence. This study was performed to provide more supplementary clues for the identification and understanding of pulmonary mucoepidermoid carcinoma. Methods: We reviewed the medical records since January 1, 2000 to December 31, 2018. The patients’ medical records，including age at the time of diagnosis , gender, smoking history, preoperative evaluations, operative procedures, tumor location, tumor size, tumor stage, lymph node metastasis, pathological markers, prognosis and survival information were extracted and reviewed. Categorical variables were presented as parameters and percentages. A comparison was performed between patients with high and low grade of pulmonary mucoepidermoid carcinoma. Results: 20 patients were identified and the age span is from 18 to 67 year-old with the average age is 45. Mucoepidermoid carcinomas were commonly found in men（60%）. 80% patients had clinical presentations and the positive rate of tumor markers was 78%, although no specific tumor markers were found. TTF-1 were negative in all cases. ALK rearrangement was identified in a non-smoking woman with high grade pulmonary mucoepidermoid carcinoma. Surgery is the main procedure. 3-year survival rate is 72% and 80% patients achieved disease-free alive. High-grade patients tend to harbor older age (p=0.035), larger tumor volume (p=0.026) and higher index of ki-67(p=0.0005). Conclusions: Pulmonary mucoepidermoid carcinoma could occur in a wide age span. Early diagnosis and complete surgical resection may promise a good prognosis. Grading is a key factor to predict the overall survival time. Combined TTF-1 and MAML2 will benefit the identification of pulmonary mucoepidermoid carcinoma from other lung tumors. Future prospective randomized controlled trials and larger, multi-centric series are needed.