The probability of malignancy for pure ground glass nodules is about 18%, thus the probability of benign is about 82%, and the risk of malignancy is also related to size and shape.
Lung nodules are lung masses ≤3 cm found on imaging such as chest CT and can be categorized into solid nodules, pure ground glass nodules and mixed ground glass nodules based on their density. The malignancy rate of pure ground glass nodules is about 18%, which is higher than that of solid nodules (7%) and lower than that of mixed ground glass nodules (63%).
A pure ground glass nodule with a malignancy rate of 18% gives a probability of a benign nodule of about 82%. That is, there is about an 18% chance that a pure ground-glass nodule is the result of a malignancy such as bronchopulmonary carcinoma or metastatic carcinoma of the lungs, whereas the probability that it is the result of a benign condition such as pneumonia, charcoal deposition, or focal fibrosis is about 82%.
The risk of malignancy of lung nodules is also closely related to the size of the lesion, e.g., the malignancy rate of lung nodules less than 5 mm is <1%, whereas lung nodules >8 mm have a 15% or more risk of being malignant. Ground glass nodules should also be evaluated with reference to the presence of signs such as lobulation and burr sign. Patients are advised to consult a specialist for a comprehensive analysis of the possible etiologies and to follow the prescribed treatment.