Definition: a single, <3 cm discrete, well-marginated, rounded opacity, surrounded by normal lung, with no lymphadenopathy or pleural effusion.
It is often an incidental finding, especially with increased use of CT scan but still it could be an be early, curable malignancy.
1. Benign (70%): Granuloma, Hemartoma, Bronchogenic cyst, AV malformation, Rheumatoid nodule
2. Malignant (39%): Bronchogenic carcinoma, Metastases from breast, heard, neck , colon.
• History: h/o cancer, smoking, age (<30 years = 2% malignant)
• CT: size/shape, calcium deposits, Lymphadenopathy, effusions, bony destruction, compare with old studies.
• High-risk features for malignancy:
- ≥2.3 cm diameter,
- >60 years old,
- >1 ppd current smoker,
- no prior smoking cessation