Ground glass shadows are usually seen in the lungs and are an imaging description. Ground glass shadows can usually be caused by lung inflammation, tuberculosis, and tumors. 1. Lung inflammation: Viral pneumonia, mycoplasma pneumonia and many other inflammatory diseases of the lungs can be seen on the imaging of the lungs appearing round-like glassy shadows with a density slightly higher than that of the lung tissue. 2. Tuberculosis: some patients with tuberculosis may show nodular hyperdense shadow with wide and uniform distribution, and both lungs may also show glassy changes. 3. Tumor: Lung tumors can manifest as round or irregularly shaped ground-glass nodules. It is mostly seen in lung adenocarcinoma which mainly grows close to the wall. In addition, atypical adenomatous hyperplasia may also present as ground-glass shadow. There are other causes of ground-glass shadow, and patients are advised to seek medical treatment as soon as possible to avoid delaying the condition.