Prognostic factors of primary pulmonary mucoepidermoid carcinoma: a clinical and pathological analysis of 34 cases.

Pulmonary mucoepidermoid carcinoma (PMEC) is a rare malignant neoplasm, and little is known about the prognostic factors. The aim of the present study was to identify the relationship between tumor's histological features and clinical behaviors and to analyze the survival of patients with PMEC. A total of 34 patients with PMEC from May 2001 to April 2013 were included in the investigation. The clinical data, radiological manifestation, pathological findings, treatment strategy, and prognoses of all patients were analyzed retrospectively. The patients were classified into low-grade group (n = 25) and high-grade group (n = 9), based on histological grades. High-grade PMEC was more common in patient with elevated serum carcinoembryonic antigen (CEA) (P = 0.033), advanced tumor-node-metastasis (TNM) stage (P = 0.004) and lymph node metastasis (P < 0.001). The 5-year PFS and OS of all patients were 75.7% and 83.6%, respectively. Age, pathological grade, lymph node metastasis and TNM stage were correlated with the survival of PMEC patients. Lymph node metastasis was an independent predictor of OS (HR, 0.080; P = 0.029) and PFS (HR, 0.090; P = 0. 004). A higher tumor histological grade indicated a more aggressive behavior. Patients who had undergone complete resection for PMEC without any lymph node metastasis were expected to be cured.