3. DEFINITION
• A solitary pulmonary is defined as a discrete,
well marginated, rounded opacity less than or
equal to 3cm in diameter that is completely
surrounded by lung parenchyma does not touch
the hilum or mediastinum and is not associated
with adenopathy, atelectasis or pleural effusion.
• About 40% malignant
• Lung mass: greater than 3 cm
▫ Vast majority are malignant
11. • Simulants of a solitary pulmonary nodule
External object
Pseudotumor (fluid in fissure)
Pleural plaque or mass
12. PRIMARY GOAL
• The goal of radiologic evaluation of suspected
solitary pulmonary nodules is to noninvasively
differentiate benign from malignant lesions as
accurately as possible
13. • Standard radiologic evaluation of a suspected
solitary pulmonary nodule includes careful
review of findings at chest radiography and,
when appropriate, comparison with findings at
prior radiography, chest fluoroscopy, and CT
and correlation with clinical signs and symptoms
14. WORK-UP OF SPN
• CXR
• Sputum Examination
• CT Scan
• PET Scan
• Bronchoscopy
• Biopsy
▫ TTNA, FNA
▫ VATS, Open
15. LESION DETECTION
• Pickup - this is a variable factor depending on
the radiologist’s experience
• Over reading / under reading
• High kV - better rate of detection
• Digital radiograph - this allows manipulation on
a computer monitor and a higher rate of
detection
18. IS IT BENIGN OR MALIGNANT?
Start with
• Clinical History
• Age- Risk of Malignancy increases with age
• Sex
• Individual habits- smoking
• Familial history- malignancy
19. • Morphology of nodule
• Rate of growth
▫ Serial follow up
▫ Doubling time
20. Doubling Time
• 25% increase in diameter results in doubling of
volume
• Non-malignant disease: less than 1 month or
greater than 400 days
• Malignant lesions: 30 to 400 days
23. SIZE
• Has a very limited role in evaluating the nature of lesion
• SPN is evident on cxr only if size is >9mm
• Nodule measure 0.5 to 1cms – 68% benign
1 to 2 cms – 50% benign
2 to 3 cms – 80% malignant
>3 cms - 97% malignant
• However micronodules <5mm may have a very high
malignant potential.
• Chances for malignancy increases as the size of the
nodule increases.
24. LOCATION
• Attached nodule-contact surface of nodule >50%
of diameter attached to fissure /pleura/vessel is
benign.
• Purely intraparenchymal-
▫ Primary ca - mostly upper lobes(mostly right)
▫ Metastatic SPN- outer one-third of lung fields
▫ Benign – equal distribution in upper and
lower lobes
26. • Spiculated Corona radiata sign
Fine linear strands extending
4-5 mm outward
27. • The CT halo sign indicates ground-glass attenuation
surrounding a pulmonary nodule. The halo of
ground-glass attenuation pathologically represents
pulmonary hemorrhage, tumor infiltration, or
nonhemorrhagic inflammatory processes.
• Initially, the sign was regarded as a specific sign of
invasive pulmonary aspergillosis, but it has a wider
differential diagnosis and can be caused by a variety
of other conditions such as infection, neoplastic, and
inflammatory diseases.
28. Positive bronchus sign
• A positive bronchus sign is a CT concept where a
hypoattenuating tube (bronchus) leads directly
to a lung nodule.
• The hypoattenuating tube may extend into the
tumor. Although the sign is not specific for a
malignant lesion, its presence indicates that a
high yield would be obtained by a transbronchial
biopsy
29.
30. CT SCAN
• The advent of CT has led to improved
recognition of the frequency with which
nodules are nonsolid, partly solid, and solid.
Aerated lung parenchyma is visible through a
nonsolid (ground-glass) nodule, while a partly
solid nodule contains solid regions that mask an
aerated lung
31. • Partly solid nodules are more likely to be
malignant than nonsolid nodules
• Although solid nodules are the most common
type of nodule, they are less likely to be
malignant than are partly solid or nonsolid
nodules.
• Inflammatory diseases of the lung, particularly
tuberculosis and mycoses, usually produce solid
nodules that may eventually calcify and permit
the designation of benign disease.
32. CAVITATION
• Cavity – gas filled space may or may not be
accompanied by a fluid level.
• Thin <4mm & smooth walls – Lung abscess /
benign lesion.
• Thick >16mm and irregular – malignant lesions.
• When a cavity contains a mass within it will
form a crescent of air in between the mass and
the cavity wall – Meniscus sign.
• Seen with fungal balls (mycetoma) / abscess/
necrotic neoplasms.
35. • Malignant nodule
▫ Stippled
▫ Punctate
▫ Eccentric
▫ Central calcification in spiculated SPN
36. PET Scan
• 18-FDG (fluorodeoxyglucose)
▫ increased uptake by metabolically active cells
▫ does not enter glycolysis
• Allows more accurate identification of tumors,
lymph nodes, and metastatic disease
• Benign disease Malignant disease
▫ 96% sensitivity 96% sensitivity
▫ 88% specificity 77% specificity
37. Limitations of PET Scans
• Spatial resolution 7-8 mm thus unreliable for
lesions less than 1 cm
• False positives in infection or inflammation
• False negatives in tumors with low uptake such
as bronchoalveolar cell carcinoma
38. Bronchoscopy
• Limited role
• Transbronchial needle aspiration of mediastinal
lymph nodes
• Useful for large central lesions and
endobronchial lesions
• Can detect infection
• No use in peripheral nodules
39. Biopsy
• CT guided
▫ Transthoracic needle aspiration (TTNA)
▫ Fine needle aspiration (FNA)
• Surgical
▫ Video Assisted Thoracic Surgery (VATS)
▫ Open
40. TTNA
• Increasing utilization of TTNA
• Not indicated for patients committed to surgery
• Accuracy for detecting malignancy 64-100%
• Yield increased when cytopathologist present
• Three results:
▫ Malignant
▫ Specific benign, e.g. TB
▫ Non-specific benign, e.g. bronchoalveolar hyperplasia
41. Surgical biopsy
• VATS (Video Assisted Thoracic Surgery)
▫ peripheral nodules within 2 cm of pleura
▫ solid lesions
▫ lesions not diagnosed by other means
• Open
▫ commitment to resection with curative intent
42. Summary
• SPN by definition is 3 cm or less
▫ 40% are malignant
• REVIEW PRIOR FILMS!!!
• margins of the lesion and the presence or
absence of calcification should be assessed
• Lesions that are unchanged in size over a 2-year
period may be presumed to be benign and
followed up at 6-monthly intervals for a further
2 years.
43. • No change in 2 years…no further work-up
• The presence of central or ringlike calcification also
places the lesion in the benign category
• Working up SPN