A solitary pulmonary nodule is defined as a well-circumscribed opacity less than 3 cm in diameter surrounded by lung parenchyma. Most solitary nodules are benign, but some may represent early lung cancer. Common benign nodules include granulomas, hamartomas, and benign tumors. Imaging with CT scan is important to evaluate characteristics like size, shape, margin, internal features, and doubling time, which provide clues about whether a nodule is benign or malignant. Tissue sampling through biopsy may be needed for diagnosis in indeterminate cases.

1. SOLITARY PULMONARY NODULE
Dr.Santosh Atreya
Phase-B Resident
Department of Radiology & Imaging

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3. A solitary pulmonary nodule, according to the -
Nomenclature Committee of the Fleischner Society,is
defined as a discrete, well-marginated, nearly circular
opacity less than or equal to 3 cm in diameter that is
completely surrounded by lung Parenchyma.
Does not touch the hilum or mediastinum, and is without
associated atelectasis or pleural effusion.
Definition

5. • Most solitary pulmonary nodules are benign. However, they
may represent an early stage of lung cancer. Lung cancer is
the leading cause of cancer death in the United States,
accounting for more deaths annually than breast, colon, and
prostate cancers combined.
• Over 1 million nodules are detected each year as an incidental
finding, either on chest radiographs or thoracic computed
tomography (CT) scans.
• 40% of solitary pulmonary nodules are malignant, with other
common lesions being granulomas & benign tumours.

6. Classification
Malignant: Primary nodule
Secondary nodule
Lymphoma
Plasmacytoma
Alveolar cell carcinoma
Benign: Hamartoma
Adenoma
Connective tissue tumours
Granuloma: Tuberculosis
Histoplasmosis
Paraffinoma
Sarcoidosis

7. Infection:
Round Pneumonia Pulmonary infarct
Pulmonary Haematoma
Collagen Diseases
Rheumatoid arthritis
Wegener’s granulomatosis
Abscess
Hydatid
Amoebic
Fungi
Parasites
Rounded atelectasis
Round pneumonia
Congenital:
Bronchogenic cyst
Pulmonary Sequestration
Congenital Bronchial atresia
AVM
Miscellaneous:
Impacted mucus
Amyloidosis
Intrapulmonary lymph node
Pleural:Fibroma, Tumour,
Loculated fluid
Non Pulmonary: Skin & chest wall
lesions, Artefact
Contd…

9. Size Interpretation
<3mm 99.8% Benign
4-7mm 99.1% Benign
8-20 mm 82% Benign
>20 mm 50% Benign
>30 mm 7% Benign

10. SPURIOUS LESIONS ON CXR
• Nipple shadow
• Pleural based lesions
• Chest wall lesions
• Skin nodules
• Artifacts due to clothing
• Screen artifacts
Benign granuloma and primary bronchogenic
carcinomas account for 80% of cases of SPN

11. Classic example of “hyposkilia” – the patient had
never been examined by physician.
This patient had
neurofibromatosis 1

12. This lady also came for a CT guided biopsy
of a left mid-zone lesion

13. Rib fracture callus

14. SPURIOUS LESIONS ON CXR
• Nipple shadow
• Pleural based lesions
• Chest wall lesions
• Skin nodules
• Artifacts due to clothing
• Screen artifacts
Benign granuloma and primary bronchogenic
carcinomas account for 80% of cases of SPN

15. IMAGING OF SPN
• CHEST RADIOGRAPH
• CT SCAN
• MRI
• FDG-PET / SPECT

16. How to detect SPN
Lesion ??
•
•
•
•
•
Pickup – Depends on the radiologist experience
Experience & Expertise
The “Ten-Thousand” hours rule
 High kV
Digital radiograph - these allow manipulation on a computer monitor
and a higher rate of detection
The principle holds that 10,000 hours of
"deliberate practice" are needed to
become world-class in any field.

17. • A nodule is assessed for its size,shape &
outline and for the presence of calcification
or cavitation.
• A search is made for associated abnormalities
such as bone destruction,effusions,lobar
collapse,septal lines & lymphadenopathy.

18. • Several radiologic characteristics found on CT
scanning and radiography may help to suggest
whether a lesion is benign or malignant. These
include the following:
• Size
• Shape
• Location
• Margin
• Doubling Time
• Internal characteristics
• HRCT is the most
sensitive and specific
for assessing the size,
shape, calcification and
margin of a nodule

19. MORPHOLOGICAL CHARACTERISTICS OF
SPN
1. SIZE
Size less than 10 mm : Difficult to appreciate
on a plain film & often appear as a
“Smudge” shadow rather than a mass.
But readily seen on CT.

20. 2.SHAPE
CARCINOMAS : Irregular,Spiculated
or Notched margins.
Lobulation occurs in 25% of benign
nodules.
BENIGN :
ROUND/OVAL/SMOOTH
On occasions Infective Processes
have a round appearance which is
usually ill defined.

21. 3.LOCATION:
Nodules that are attached to pleura, vessels, or fissures are
likely to be benign
• Central tumors: small cell carcinoma, squamous
cell carcinoma
• Peripheral tumors: adenocarcinoma, large cell carcinoma
• Metastasis usually basal and sub pleural
• Benign lesions are equally distributed throughout the lungs

22. 4.MARGIN
• MALIGNANT :
irregular/spiculated/lobulated
( radial extension of the tumor cells along the lymphatics,
small airways or blood vessels)
• BENIGN : smooth/sharp
Metastases and carcinoid tumors have sharp, smooth
edges
21% of well defined nodules are malignant

23. Fine linear strands
extending 4-5 mm
outward
Spiculated on CXRs
84 – 90% are malignant
Corona radiata sign

24. Bronchogenic carcinoma. (A) Relatively
well-defined mass. (B) Ill-defined solitary
nodule.

25. She has a 2.2 cm sized nodule in the
right mid-zone

26. Next Steps
• A – Do nothing - old granuloma
• B – Aggressive - suspected
malignancy
• C – Give antibiotics or ATT
• D – Investigate further

27. Confirm intra-pulmonary
location

28. • A lateral film is often
necessary to confirm
that a lesion is
intrapulmonary before
investigating further.

29. This lesion is intra-pulmonary –
seen on both frontal and lateral
radiographs in the lung

30. • Typically an intrapulmonary
mass forms an acute angle
with the lung edge whereas,
extrapleural & mediastinal
masses form obtuse angles.
Extra Pleural Mass

31. • Name:Rokaya
Age: 60 Yrs
Address:Farid-
pur
C/O :Pain in
lower back for
3 years.
Recently she
developed
mild chest
pain.

32. Criteria for benignity
A - Calcification
B - Absence of enhancement
C - No Change in size for 18 months

33. Completely calcified -
benign
Engulfed calcific focus by a
malignant lesion

34. 5.Doubling Time
• Volume doubling time is the time required for a lesion to double its
volume
• Malignant lesions : Doubling time of 1-6 months
• Benign lesions: Do not change their size for 18 months. such as
granuloma, hamartoma, bronchial carcinoid, and rounded atelectasis.
• In general, doubling times of less than 20 days suggest infections.
• An increase of 28% in nodule diameter indicates doubling

35. CT scan in an 80-year-old man: 2.5-cm
right upper lobe nodule at posterior
segment
Repeat CT scan 2 months later: Rapid
interval enlargement. Volumetric
doubling time was 35 days. FNAB
revealed mixed small cell and non–small
cell carcinoma.

36. A B C
April 06 June 08
Completely calcified and no
growth in 2 years -
benign

37. plain post-contrast
No enhancement whatsoever -
benign

38. May July
She shows a significant
increase in size over
2 ½ months

39. Plain Post-contrast
Contrast-enhanced study
shows
enhancement

40. Benign:
• Diffuse
• Central
• Popcorn
• Laminated
6.INTERNAL CHARACTERISTICS OF SPN
 Potentially Malignant
• Stippled
• Eccentric
Calcification Patterns

41. CENTRAL
CALCIFICATION

42. DIFFUSE,SOLID: GRANULOMA CONCENTRIC/TARGET

43. POPCORN CALCIFICATION

44. Eccentric dense calcification in
right lower lobe carcinoid
Amorphous calcification in non
small cell ca lung

45. • LESION WITH WALL THICKNESS
< 4 mm -LIKELY BENIGN
> 16 mm- LIKELY MALIGNANT
4-16 MM – INDETERMINATE
• IRREGULAR – LIKELY MALIGNANT
• THIN SMOOTH – LIKELY BENIGN
Cavitation
Malignant cavitation

46. • Air bronchograms and
pseudocavitation more commonly
malignant
• Desmoplastic reaction to the tumor
distorts the airway causing
narrowing and/or irregularity of
the small bronchi in relation to the
tumor
• Seen as cystic glandular spaces
within the mass
PSEUDOCAVITATION / AIR BRONCHOGRAMS

47. • Angioinvasive Pulmonary
Aspergillosis
• Blood clot in a cyst
• Complicated hydatid
disease
• Ca arising in a cyst
• Pulmonary gangrene
AIR CRESCENT SIGN
Early CT finding is a rim of
ground-glass opacity
surrounding the nodules (CT
halo sign).
Angioinvasive aspergillosis. CT section at the level of
the aortic arch shows two nodules with eccentric
Cavitation and “air crescent sign” . These findings in
this neutropenic patient are highly diagnostic of
angioinvasive aspergillosis.

48. Usually seen in benign lesions
like lung abscess, infected
cyst or cavity
AIR FLUID LEVEL

49. Name the sign??

50. Small nodules adjacent to larger
nodule or mass,predictor of benign
disease like granulomatous
diseases
Galaxy sign : satellite nodules in
sarcoidosis
Presence of satellite nodules in lung
tumors is considered as locally
advanced tumor
SATELLITE NODULES

51. Small pulmonary artery leading
directly to a nodule
Seen in AVF, hematogenous
metastasis, infarct
FEEDING VESSEL SIGN

52. • A pulmonary lesion that directly abuts,
narrows or occludes bronchial lumen is more
likely to be malignant
• Also seen in tuberculoma, pulmonary infarcts,
Inflammatory masses
• This sign helps in whether transbronchial or
trans thoracic biopsy helps in histological
diagnosis
POSITIVE BRONCHUS SIGN

53. POSITIVE BRONCHUS SIGN

54. Next steps
• A - Trial of therapy
• B - CT guided biopsy
• C - Bronchoscopy guided biopsy
• D - Lobectomy

55. CT – guided
biopsy

56. Tips during biopsy
• Biopsy not FNAC
• At least 5 cores
• Material for EGFR mutation studies

57. Gun-cannula technique – stylet in
cannula and gun

58. Foot pedal and in-room monitor allow accurate control along with
CT fluoroscopy

59. SPN
PA radiograph
BENIGN
Calcification
Lesion external or extra-
pulmonary
I
INDETERMINATE
Old X-rays
BENIGN
No change over 18
months
INDETERMINATE
CT scan / PET CT
BENIGN
No enhancement or
uptake ,Calcification
INDETERMINATE
BIOPSY

60. NOTE
• Risk of malignancy increases with age. For
individuals younger than 39 years, the risk is
3%. The risk increases to 15% for individuals
aged 40-49 years, to 43% for persons aged 50-
59 years, and to more than 50% for persons
older than 60 years.

61. Sometimes, some lesions are
characteristic

62. SOME COMMON BENIGN SPN

63. GRANULOMA
Commonest are Tuberculomas
Tuberculoma: more common in the upper
lobes & on the right side.
 Well defined ; 0.5-4 cm.25% are lobulated.
 Calcification frequent.
 80% have satellite lesions. Cavitation is
uncommon.
 Usually persists unchanged for years.

65. PULMONARY HAMARTOMA
• Benign pulmonary mass containing connective tissue ,
Cartilage , fat , smooth muscle , marrow , and bone
• Most common location – periphery of the lung
• X ray chest – spherical ,lobulated , well defined nodule
• Popcorn like calcification
• Fat density within the mass is a diagnostic feature
• ge > 40yrs (96%)

66. Central Lucencies :
• Fat
• 50 % contains fat & 30 % contains
calcium

67. The parenchymal lesion in this computed tomography (CT) scan
demonstrates low attenuation within the lesion, indicating the
presence of fat. Fat density is observed only in hamartoma and
lipoid pneumonia. The likely diagnosis is hamartoma

68. • X ray – well
circumscribed
lesion with
lobulated
outline
• CT - Feeding vessels and
draining vein can be
seen
• It can be confirmed on
CT
• PULMONARY
ANGIOGRAPHY RARELY
INDICATED
Lobulated,well marginated
nodule in the lower lobe
AVM
Feeding artery (arrow) and an enlarged
draining vein (arrowhead).
Simple pulmonary arteriovenous malformation. CT
scan at the level of the lung bases shows a well-defi ned,
smooth,
round nodule. Note:That the feeding vessel is about half the
diameter
of the fi stula.

69. Nidus of malformation
Pulmonary angiogram helps confirm
arteriovenous malformation. Note the early
draining vein (arrows)

70. ROUND PNEUMONIA
• Inflammatory pseudotumour
• Some times pneumonic
consolidation assumes a shape
And density similar to
pulmonary neoplasm
• Careful study reveals irregular
margin and air bronchogram
• Common in children
• May persists after recovery
from infection

71. VANISHING TUMOR
• Sharply marginated
collection of pleural fluid
contained either within
an interlobar pulmonary
fissure or in a subpleural
location adjacent to a
fissure
• Can occur on minor
fissure , oblique fissure
• Most of them are < 4 cms

72. BRONCHIAL CARCINOID
• Typical triad –
Well defined,round lobulated lesion
At the bifurcation
Eccentric calcification
account for up to 5% of lung cancers.
These tumors are generally small (3-4
cm or less) when diagnosed and occur
most commonly in persons under age
40.

73. Nodule with eccentric
calcifications (arrow) obstructing
the posterior segmental
bronchus of the right upper lobe.
High-resolution CT scan shows a
well-defined, round, partially
endobronchial nodule (arrow) in the
lateral subsegmental branch of the
anterior segmental bronchus of the
left upper lobe.

74. On a contrast-enhanced CT scan
(mediastinal windowing), the
nodule demonstrates marked
contrast enhancement and
mimics a vascular structure
On a contrast-enhanced CT scan
(mediastinal windowing), the
nodule demonstrates marked
contrast enhancement and mimics a
vascular structure

75. ROUND ATELECTASIS
• Chronic atelectasis that resembles mass-Pseudotumour
 Can be differentiated from malignancy using CT -
• Peripherily located , wedge shaped opacity
• Rounded or wedge shaped mass, forms an acute angle with adjacent thickened
pleura , commonly at lung base
• Crow feet / comet tail of vesssels sweeping into the margin of this opacity
• Air bronchogram visible in the centre portion of mass.
• Homogenous contrast enhancement of the atelectatic lung.
• Volume loss in the ipsilateral hemithorax.

76. • Conventional
tomographic scan of the
chest in a lateral
projection shows a large
subpleural mass
(arrowhead) in the right
lower lobe of the lung. A
curvilinear opacity
(arrow), the comet tail
sign, arises from the
inferior pole of the mass
and courses toward the
hilum.

77. CONTRAST ENHANCEMENT
- S/O• NODULE ENHANCEMENT < 15 HU
BENIGN LESION
• NODULE ENHANCEMENT > 15 HU – S/O
MALIGNANT LESION
• SENSITIVITY - 95 -100%
• SPECIFICITY -70 -93 %

78. When is CT needed??
 When CXR demonstrates
• Uncalcified nodule
• Nodule not stable for 18
months
• Failure of symptomatic
infiltrate to clear in 4-6
weeks.

79. Disadvantages of MRI
• Poor resolution
• Cardiac and respiratory motion artifacts
• Difficulty in detecting lesion < 1 cm lesion
• Not useful in peripheral SPN due to signal loss

80. PET SCAN
•
•
•
Highly valuable noninvasive tool
It is 95% sensitive for identifying malignancy and 85%
specific
False positive results may occur in lesions that
contain active inflammatory tissue (histoplasmomas)

81. ROLE OF FDG-PET
• Malignant cells have upregulated metabolisms and
proliferate rapidly.This results in marked uptake of
FDG
• False negative results due to - < 10 mm
• False positive results are due to –Active TB ,
Histoplasmosis , Rhematoid nodules ,Aspergillosis ,
wegeners granulomatosis
• Possibility of malignancy with negative FDG-PET is
<5%

82. Axial CT
Axial
PET

83. • TEXTBOOK OF RADIOLOGY AND IMAGING BY DAVID
SUTTON
• HAAGA
• CHAPMAN & NAKIELNY’S
• Evaluation of solitary pulmonary nodule : INDIAN
JOURNAL OF RADIOLOGY
Bibliography

84. THANK YOU
6/4/2017 83