A ground glass lung result from a CT scan is a non-specific finding that describes an area characterized by a small increase in lung density, explains the National Institutes of Health. Patients with early diffuse pulmonary infiltrative diseases are more likely to present with an area of ground glass opacity in the lung.
Although a lung may have an opaque area described as having a ground-glass appearance on the CT scan, the bronchial walls and vascular structures of the lung remain visible, according to the NIH. This type of pulmonary opacity may be diffuse or patchy and is a significant finding because it may represent an abnormality that is active and treatable.
There can be numerous causes of a ground glass lung condition such as sarcoidosis or pulmonary fibrosis, note the NIH. A ground glass lung opacity may also be observed in conditions such as alveolar proteinosis, desquamative pneumonitis, hypersensitive pneumonitis and drug-induced or radiation-induced lung disease.
If an area of ground glass opacity persists in the lung, it is usually classified as an adenocarcinoma, a classification that ranges from premalignant lesions to invasive disease, explains the Mayo Clinic. Lesions are generally slow growing, but because their significance is unknown, optimal management and follow-up procedures are not clearly understood. As of 2015, ground glass lung opacities are an area of intensive research to better understand their significance and health risks.