Lung lesions are not necessarily cancerous, as lung lesions can be seen in many diseases other than cancer. For example, infectious factors lead to bronchitis, pneumonia, and lung abscesses, such as those caused by viruses, bacteria, mycoplasma, chlamydia, rickettsiae, and pathogens such as Mycobacterium tuberculosis and fungi. There are also non-infectious lung lesions, such as diffuse interstitial fibrosis of the lungs and bronchiectasis, for which the cause has been clearly identified, as well as idiopathic bronchiectasis. There are also space-occupying lesions of the lungs, such as benign tumors, and in addition to cancer there are teratomas, misshapen tumors, as well as alveolar protein deposition disease and lung stones. For diagnosis, in addition to imaging CT or MRI, biopsies of lung lesions can be taken for pathologic examination to clarify the cause of the disease.