Pulmonary Nodule

What is a Pulmonary Nodule?

A pulmonary nodule is a small, round or oval-shaped abnormality in the lung that appears on imaging studies, particularly CT scans. Nodules are typically defined as opacities measuring less than 3 cm in diameter. Anything larger is usually classified as a mass.

Imaging Appearance

On chest CT, pulmonary nodules appear as:

• Solid nodules: Completely opaque, obscuring underlying vessels
• Ground-glass nodules: Hazy opacity where vessels are still visible
• Part-solid nodules: Mix of solid and ground-glass components

The presence of calcification (calcium deposits) within a nodule often suggests a benign cause.

Clinical Significance

Why is this finding important?

Pulmonary nodules require evaluation because they can represent:

Benign Causes (Most Common):

• Granulomas from old infections (TB, fungal)
• Hamartomas (benign tumors)
• Inflammatory lesions
• Scarring from prior pneumonia

Malignant Causes (Require Exclusion):

• Primary lung cancer
• Metastases from other cancers
• Carcinoid tumors

Risk Factors for Malignancy

Your doctor considers these factors:

• Age ＞ 40 years
• Smoking history (current or former)
• Nodule size ＞ 8 mm
• Spiculated or irregular margins
• Upper lobe location
• Growth on serial imaging
• No calcification

Follow-Up Recommendations

Based on size and risk factors, your doctor may recommend:

Small nodules (＜ 6 mm):

• Low-risk patients: No routine follow-up
• High-risk patients: Repeat CT in 12 months

Medium nodules (6-8 mm):

• Follow-up CT in 6-12 months
• May require additional imaging

Larger nodules (＞ 8 mm):

• Earlier follow-up (3-6 months)
• May require PET scan or biopsy

What Should You Do?

1. Don't panic - Most nodules are benign
2. Review risk factors with your doctor
3. Follow imaging protocols exactly as prescribed
4. Consider smoking cessation if applicable
5. Ask about low-dose CT screening if you're high-risk

Related Imaging Terms

• Ground-glass opacity (GGO) - May indicate early-stage adenocarcinoma
• Consolidation - Can mimic nodules
• Calcification - Usually indicates benign disease

Common Questions

Can a nodule disappear?

Yes, infectious or inflammatory nodules may resolve with treatment or time.

How long will I need follow-up?

Depends on nodule characteristics. Some require 2 years of surveillance; others may need longer.

Should I get a biopsy?

Biopsy is typically reserved for nodules that are growing, large (＞ 8 mm), or highly suspicious based on imaging features.

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Medical Disclaimer: This information is educational only. Always discuss your specific CT findings with your healthcare provider for personalized medical advice.