I. Malignant epithelial tumors
A. Squamous cell carcinoma (epidermoid carcinoma)
Variant:
· Spindle cell carcinoma

B. Small-cell carcinoma
· Oat cell carcinoma
· Intermediate cell type
· Combined oat cell carcinomas

C. Adenocarcinoma
· Acinar adenocarcinoma
· Papillary adenocarcinoma
· Bronchio-alveolar carcinoma
· Solid carcinoma with mucus formation

D. Large-cell carcinoma
Variants:
· Giant cell carcinoma
· Clear cell carcinoma

E. Adenosquamous carcinoma

F. Carcinoid tumor

G. Bronchial gland carcinomas
· Adenoid cystic carcinoma
· Mucoepidermoid carcinoma

H. Others

II. Malignant mesothelial tumors
A. Malignant mesothelioma
· Epithelial
· Fibrous (spindle cell)
· Biphasic

III. Miscellaneous malignant tumors
A. Carcinosarcoma
B. Pulmonary blastoma
C. Malignant melanoma
D. Malignant lymphoma
E. Others