Background: Lung cancer is the leading cause of cancer death in both men and women. In the past decade, histopathological classification of lung cancer has become increasingly important in selecting the appropriate treatment. Methods: All cases of lung cancer diagnosed pathologically in the last 2.5-year period were retrospectively identified at National Cancer Center and performed by descriptive case series design. Results: The average age of our participants was 62, of which 82.2% were men. A total of 214 cases of lung cancer were reported, including 142 (66.4%) squamous cell carcinoma (SCC), 34 (16%) adenocarcinoma (AC), 4 (1.7%) NSCLC, 29 (13.6%) small cell carcinoma (SmCC) and 5 (2.3%) cases of other/unspecified type. Based on only morphology, initially 32 (17.7%) cases of NSCLC were diagnosed, whereas after immunohistochemistry (TTF-1 or NAPA positive/p63 negative, and vice versa) staining, this category reduced to 2.2%. Conclusions Among both males and females, SCC which is highly related to smoking was the most common histologic type of lung cancer. Our results showed that an approach of using only a two-antibody panel (p63 and TTF-1) might help in the reduction of diagnostic category of NSCLC-NOS significantly.