Patchy, dense shadows visible in the left upper lung can be seen in a variety of diseases, the most common of which are pulmonary Wegener’s granulomatosis, bacterial pneumonia, fungal pneumonia, mycoplasma pneumonia, and tuberculosis. In recent years, the understanding of lung cancer imaging has deepened and the diagnostic level of lung cancer imaging has been improved. The number of missed and misdiagnosed cases of alveolar carcinoma and peripheral adenocarcinoma, which appear as patchy and lamellar shadows, is slowly decreasing, and these cases need to be differentiated from pulmonary Wegener’s granulomatosis, pneumonia, and tuberculosis. Due to the lack of clinical work experience, misdiagnosis of some other diseases with patchy shadows as the basic manifestation has occurred from time to time due to less look and incomplete understanding and failure to fully integrate clinical information, such as misdiagnosis of fungal pneumonia and malignant histiocytic hyperplasia as infiltrative pulmonary tuberculosis.