Our immunohistochemical results have suggested that the tumor cells stained positively for TTF-1, EMA, CK7, cytokeratin and CD31 that indicate the tumor originates from the epithelium, especially from type-II pneumocytes or Clara cells, but not from endothelium and the mass was decided as a sclerosis haemangioma of lung. The gene discussed is PECAM1; the disease is neoplasm.