Solitary Pulmonary Nodule (SPN)

Question 1

What are the characteristics of a solitary pulmonary nodule on CXR

Answer 1

Coin lesion
1. Under 3 cm
2. Isolated
3. Rounded opacity
4. Visible on chest CXR / CT surrounded by healthy lung tissue
5. Asymptomatic

Question 2

What is the etiology of SPN

Answer 2

Possible malignant
*dependent on patient population
Possibly benign
*most SPN are infectious granulomas
*around 5% are benign neoplasm

Question 3

What is the evaluation goal of SPN

Answer 3

1. Avoid invasive procedures if benign
   *justify observation, identify and respect malignant SPN in those who will benefit
2. Look at old imaging studies

Question 4

What will influence the SPN

Answer 4

1. Patient age (Rare under 30)
2. Known tobacco use
3. Prior malignancies

Question 5

What percentage of SPN have a potential for malignancy

Answer 5

10 to 68%

Question 6

What can be used to diagnose a SPN

Answer 6

1. History and Physical examiantion
2. Review prior imaging
   *size, shape, calcification

Question 7

What is the estimation of doubling when considering if a SPN is malignant

Answer 7

Rapidly growing
*doubling time <30 days (infection)
Stable lesion
*doubling time >465 days (benign)

Question 8

How does size correlate to malignancy rate

Answer 8

1. Size 2 to 5mm (1% malignancy rate)
2. Size 6 to 10mm (24 % malignancy rate)
3. Size 11 to 20mm (malignancy rate 33%)
4. Size 21 to 45mm (malignancy rate 80%)

Question 9

What are the benign and malignant calcification patterns of SPN

Answer 9

Benign
*dense in a central or laminated pattern
Malignant
*sparse calcification, stippled or eccentric
*cavitary lesions with thick walls (over 16mm)

Question 10

How does the SPN shape determine if its benign or malignant

Answer 10

Benign
*smooth, well-defined edge
Malignant
*ill defined margins
*spiculated, lobular, perioheral halo

Question 11

How to determine tx of SPN

Answer 11

1. Establish probability of malignancy form clinical and radiologic info
   *low
   *intermediate
   *high
2. All patients must have estimate of likelihood of malignancy
3. Chest CT indicated for any sus SPN

Question 12

How to be considered a low probability of cancer

Answer 12

1. <30
2. Lesion stable >2 years
3. Expected pattern of benign calcification

Question 13

What is the management for “low” probability cancer

Answer 13

1. Serial imaging studies at regular intervals
   *every 3 months for 1 year
   *then every 6 months for a second year
2. Consider high resolution CT early on to obtain a more detailed baseline image

Question 14

What are the recommendations of management for intermediate probability of cancer

Answer 14

Obtain a diagnostic biopsy
1. Transthoracic needle aspiration (TTNA)
*higher diagnostic yield
*false positive rates (20-30%)
*complications are higher
2. Bronchoscopy
*diagnosis 10-80% of the time
*results for lesions under 2cm is low
*complications are low

Question 15

What are other options to screen for intermediate probability of cancer

Answer 15

1. Positron emission tomography (PET)
   *good if inconclusive CT
   *disadvantages, false negatives can occur, not for SPN under 1cm
2. Sputum cytology (central lesions)
   *very specific lack sensitivity
   *for patients who cannot tolerate invasive diagnostics
3. Video assisted thoracoscopic surgery (VATS) resection

Question 16

How to manage a high probability SPN

Answer 16

1. Proceed directly to resection with staging if no CI to surgery
   *biopsy usually not indicated