Solitary Pulmonary Nodule

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.

Etiology:
1. Benign (70%): Granuloma, Hemartoma, Bronchogenic cyst, AV malformation, Rheumatoid nodule
2. Malignant (39%): Bronchogenic carcinoma, Metastases from breast, heard, neck , colon.

Initial evaluation
• 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, 
• spiculated,
•  >60 years old, 
• >1 ppd current smoker, 
• no prior smoking cessation

Diagnostic studies

1. Positron-Emission Tomography (PET)
Whether positron-emission tomography (PET) scanning will be useful in a patient’s workup depends on 

(1) the clinical pretest probability of malignancy, 

(2) nodule morphology, 

(3) the size and position of the nodule, and 

(4) the scanning facility available

It detects metabolic. activity of tumors, also useful for surgical staging as it may detect unsuspected metastases, and useful in deciding which lesions to biopsy vs. follow with serial CT.

2. Transthoracic needle biopsy (TTNB): if technically. feasible, 97% will obtain definitive tissue for diagnosis.

3. Video-assisted thoracoscopic surgery (VATS): for percutaneously inaccessible lesions; highly sensitive and allows resection; has replaced thoracotomy.

4. Biopsy: A biopsy of a lung nodule should be performed to determine whether it is malignant.  Biopsy of a solitary pulmonary nodule can be performed bronchoscopically or via CT-guided transthoracic needle aspiration (TTNA).

Management (for solid Solitary Pulmonary Nodule >8 mm; .... if ≤8 mm, serial CT) 

• Low risk (<5%): serial CT (freq depending on risk); shared decision with patient and refer for biopsy

• Intermediate risk (5–60%): PET, if negative → follow low-risk protocol; if positive → high-risk protocol

• High risk (and surgical candidate): TBB, TTNB, or VATS → lobectomy if malignant

• Ground-glass nodules: longer follow up because even if malignant can be slow-growing and PET negative.