Ground glass nodule 1cm*0.8cm with unclear boundary in the upper lobe of left lung is a professional description of the lesion on imaging, and the unclear boundary of ground glass nodule is considered to be lung cancer, lung metastasis, but it may also be benign lesion, etc. 1. Benign lesions: such as lung inflammation is caused by various pathogens, which can make the local lung tissue form inflammatory exudation, which is manifested as ground glass nodules with unclear boundary on imaging, especially viral infection or fungal infection is common. 2. Lung cancer: Frosted glass nodules with unclear boundary may also be signs of lung cancer, such as adenocarcinoma in situ and lung adenocarcinoma, and most of them are in the early stage of cancer when the frosted glass nodules are 1cm*0.8cm. 3. Lung metastases: many malignant tumors in other parts of the body can develop lung metastasis and form ground-glass nodules with unclear boundary, such as choriocarcinoma, osteosarcoma, soft tissue sarcoma, etc. Previous history of malignant tumors should be suspected of metastasis. If you find 1cm*0.8cm ground glass nodule in the upper lobe of the left lung with unclear boundary, we suggest that you go to the hospital as soon as possible to get a clear picture of the nature of the nodule and then treat it accordingly.