cavitary lesions of lung_s_12 june_sst

Cavitary lesions of lung

Maj Manu Chopra

Cyst

• Air filled lesion

• Smooth and uniform wall > 1mm

• Epithelial lining +/-

• Infected cyst > surrounding lung inflammation > thick wall

2

Cavity

• Air containing space

• Wall thickness > 1mm

• A lesion that has cavitated (regardless of wall thickness)

• 10% cancers cavitate (80% are Sq cell ca)

3

How to define a cavity

a. Thickness of wallb. Smoothness / irregularity of inner liningc. Presence & character of contentsd. number

5

Cavity wall

Thick • Acute lung abscess• Primary carcinoma• Metastic carcinoma• Wegeners granulomatosisThin• Chronic lung infection Thicker cavities are more often malignant

6

Character of inner lining

• Nodular – carcinoma• Shaggy – acute lung abscess• Smooth – most of lung conditions

7

Nature of contents

• Liquid - majority• Fungus ball – freely mobile• Echinococcus cyst – water lily sign• Pulmonary gangrene – sloughed, necrotic

iceberg

8

Number of lesions

Solitary• Primary carcinoma• Ac lung abscess• Post traumatic lung cystMultiple• Metastatic neoplasm• Wegeners granulomatosis• Septic emboli

9

Cavity

• Malignant lesions - Thick, nodular wall

• Benign lesions - Thin, smooth wall

• Wall thickness-

>15mm -85% malignant

5-15mm -75% benign

<5mm -95% benign

<1mm -malignancy rare

10

Cavity

• Air fluid level- benign disease

• Focal thickening of cyst or cavity wall or fluid within cyst- s/o malignancy

11

Air crescent sign

• Air outlining or capping the superior aspect of the mass or nodule within the cavity resulting in a crescent shaped collection of air

• Gravitational shift of the mass strongly suggests mycetoma and excludes carcinoma

12

13

14

Supine

Prone

Air crescent sign

• Aspergilloma• Angioinvasive aspergillosis with septic infarction• Ca arising in a cyst• Cavitary ca• Clot in a cyst or cavity• Echinococcus• Mucous plug in cystic bronchiectasis• Papillomatosis• Pulm gangrene

15

Cavitary lesions- common

1. Abscess of lung 2. Bronchogenic carcinoma 3. Bulla 4. Cystic bronchiectasis 5. Fungus disease

16

Cavitary lesions- common

6. Honeycomb lung 7. Metastasis 8. Pneumatocele 9. Pneumocystis carinii pneumonia 10. Tuberculosis

17

1.1. Abscess

• Localized infection >tissue destruction & necrosis

• Communication with tracheobroncheal tree >cavitation & air fluid level

• Inner wall -smooth/shaggy & irregular

• Wall thickness -5 to 15 mm

18

1.1. Abscess

• Cause -Anaerobic inf, S aureus, P aeruginosa

• Often result of aspiration

• Infarction, cavitary neoplasm/ conglomerate mass

19

1.1. Abscess

• CT-

-Densely enhancing wall- variable in thickness/ irregular in contour

-Internal wall- shaggy

-Contents- low attenuation

-Air fluid level may be seen

21

22Pneumococcal pneumonia

23air-fluid level

Predisposing Factors for a Lung Abscess

• DEPRESSED GAG REFLEX

• UPPER AIRWAY INFECTION

• ESOPHAGOGASTRIC DISEASE WITH ASPIRATION

• PULMONARY DISEASE

26

1.2.Carcinoma• Diam >2cm - 60%

• Upper lobes- 2/3rd

• Margin- ill defined, irregular, or spiculated

• Shape- irregular/lobulated

• Air bronchograms or bubbly lucencies (pseudocavitation)

31

1.2.Carcinoma

• Cavitation with a thick(>15 mm) & nodular wall

• Satellite nodules absent• Calcification absent• Enhancement >15 HU • Doubling time 30 to 200 days

32

33Sq cell Ca of bronchus

34Sq cell ca of bronchus

1.3.Bulla

o Thin-walled– <1 mm o air-filled space o Contained within the lung

o 1 cm in size when distendedo Walls may be formed by pleura, septa, or

compressed lung tissueUnilocular / multilocularPoorly ventilatedDecrease in size during ventilation 35

What a bulla isn’t

o Pneumatocoele

o Cavity

o Cyst

o Bleb

36

Bulla

o Enlarge progressively over a period of months to years

o Most are associated with emphysema

o May become infected or lead to pneumothorax

37

Imaging findings

o Seen more in upper lobes

o Thin-walled, sharply demarcated areas containing no visible blood vessels

o Only portion of wall is usually seen

38

Imaging findings

o Tend to trap air

§ May become larger on expiration

o Bullae may become so large as to render the remaining normal lung almost invisible, pancaked atop the hemidiaphragm = vanishing lung syndrome

39

Infected Bulla

o Differentiation from lung abscess

§ Bulla contains less fluid § Much thinner wall § No surrounding pneumonitis § Patients less sick

o Clearing may take weeks to months40

41

42

43

1.4.Cystic bronchiectasis

• Multiple air filled cystic lesions• Thick/thin walled• Clustered • Lobar patchy or diffuse• Air fluid levels ( inf/retained secretions)• Air fluid levels at or about same height in all

the affected cysts with less fluid in the upper lobe cysts (water flows downhill)

44

1.4.Cystic bronchiectasis

• CT-1.Increased bronchoarterial diameter >1 (signet

ring sign)2.Lack of tapering- airway diam unchanched for

2 cm distal to a branching point3.Contour abnormality- cluster of grapes4.Visibility of airways in peripheral 1cm of lung

46

47Bronchiectasis

1.5.Semi invasive Aspergillosis

• In patients with low grade form of immuno-compromise (COPD, low dose cortico steroid, TB, DM, Collagen vascular disease)

• Tissue invasion and infarction over months

• Mimics appearance of active TB

• Irregular upper lobe consolidation and pleural thickening, slow progression to cavitation 48

49Semi-invasive Aspergillosis

1.5.Aspergilloma• Hyphae form a ball/mycetoma, lying free in

the cavity

• CXR- density surrounded by air within a cavity, best shown by CT (mobile intracavitary mass)-Air crescent sign

• Usually in upper lobes adjacent to pleura which almost always is thickened

50

51

1.6.Honeycomb lung

• Reflects extensive lung fibrosis with alveolar destruction

• HRCT- thick walled air filled cysts, measuring 3mm to 1cm in diameter. Cysts share wall and occur in several layers at the pleural surface

• Associated findigs- reticular opacities, traction bronchiectasis

52

54Honeycombing- idiopathic fibrosis

1.7.Metastasis

• 80%- Breast, skeleton and urogenital system

• The commonest primary tumours producing solitary pulmonary metastases- colon , kidney and breast, testicular tumours , bone Sarcomas and malignant melanoma

55

1.7.Metastasis

• Cavitation more common in sq carcinomas and sarcomas

• Cavitation of a subpleural metastasis is a recognised cause of spontaneous pneumothorax

56

57Metastases, carcinoma of cervix

1.8.Pneumatoceles

• Thin walled air filled space within lung occurs in assosciation with infection

• Haematogenous- septicaemia by S aureus, a common complication of i/v drug abuse

• Cavitation evident on later examination• Due to check valve mechanism• Causes – staph. aureus, pneumocystis carinii,• trauma

58

59staph abscess, i/v drug abuser, thin-walled cavities, effusion

60staph tricuspid endocarditis, pneu-matoceles

61Staph bronchopneumonia, pneumatocele

1.9.Pneumocystis carinii

• Cavities, usually thin walled, occasionally up to several mm in thickness, may develop

• Appearances may return entirely to normal, some residual scarring and cyst formation is common

63

64

1.10.Tuberculosis

• Post primary tuberculosis

• Start in the subapical parts of the upper lobes or in the apical segment of the lower lobes as small areas of exudative inflammation. These extend, coalesce, caseate and cavitate

65

1.10.Tuberculosis

• Consolidation patchy and nodular and may be bilateral

• Progressive infection indicated by extension and coalescence of the areas of consolidation, and development of cavities

66

1.10.Tuberculosis

• A large cavity with smaller satellite cavities, often bilateral but more advanced on one side

• Cavity walls are lined by tuberculous granulation tissue and traversed by fibrotic remnants of bronchi and vessels

67

1.10.Tuberculosis

• Cavities- single/ multiple, large/ small and thin/ thick walled

• Fluid levels are sometimes visible

• Chronic cavities- colonised by Aspergilus and other fungi, and mycetomas may develop

68

69Tuberculosis, complete destruction of the right lung

70Tuberculosis, bronchopneumonic spread to the opposite lung

71Aspergilloma , previous TB

2.Cavitary lesions- uncommon

1. Amyloidosis 2. Behçet syndrome 3. Cyst (eg, bronchial)4. Cystic adenomatoid malformation 5. Cystic fibrosis (mucoviscidosis)

74

2.1.Amyloidosis

• A group of conditions characterised by extracellular deposition of fibrillary protien

• Multiple nodular angular opacities up to several centimetres in size and grow slowly- can cavitate or calcify

• Calcification- fine stippling

75

2.1.Amyloidosis

• Alternatively diffuse reticulonodular shadowing or honeycombing due to diffuse deposition of amyloid within alveolar walls, lobular septa and pulmonary arterioles

76

77

78

2.5.Cystic fibrosis

• Increased viscosity of the bronchial secretions- bronchial obstruction- air trapping/ predisposes to bronchiectasis

• CXR- signs of air trapping with flattening of the diaphragm, bowing of the sternum and increased dorsal kyphosis, and signs of bronchiectasis

84

2.Cavitary lesions- uncommon

6. Diaphragmatic hernia 7. Langerhans cell histiocytosis 8. Hydatid cyst 9. Hydropneumothorax10. Inflammatory pseudotumors

86

2.7.Langerhens cell histiocytosis

• Earliest- ill-defined transient patchy consolidation• Fine reticulonodular pattern throughout both

lungs, predominantly in the mid and upper zones• Confirmation with lung biopsy• HRCT – a mixture of discrete nodules and cystic

spaces• As fibrosis progresses, a coarser linear pattern

appears, with development of ring shadows, honeycombing and bullae

87

88

2.8.Hydatid disease

• Echinococcal cyst

• Three layers:

(1) Pericyst/ adventitia formed of compressed host tissue

(2) Ectocyst friable middle layer

(3) Endocyst inner germinal layer from producing scolices

89

2.8.Hydatid disease• Daughter cysts- formed if viability threatened,

but in the lung the cyst is unilocular

• Approx 20% of pulm cysts bilateral

• 10% associated with hepatic cysts

• Uncomplicated pulm hydatid cysts- well-circumscribed, round or oval, homogeneous masses, up to 10 cm in diam

90

2.8.Hydatid disease

• Calcification rare

• Cysts may rupture into the pleura or bronchi

• Rupture into a bronchus- air-fluid level

• Ectocyst may separate from the adventitia so that a double walled cyst may be seen

91

92Walls of the cavity have partly collapsed, fluid level

93

Water-lily sign

Cudad LLL consolidation

2.14.Paragonimiasis

• Infected shellfish (Southeast Asia, esp Phillippines)

• Commonest reactions in the lung- formation of multiple 1-2 cm-diam cysts and broncho-pneumonic shadows which may resemble tuberculosis

• Dead flukes may calcify

97

2.19.Rheumatoid pulmonary nodules

• Necrotic nodules are usually associated with subcutaneous nodules, and are similar histologically

• Well-defined, round opacities up to 7 cm in diameter and may be single or multiple and may cavitate

104

2.19.Rheumatoid pulmonary nodules

• Caplan's syndrome- rheumatoid nodules against a background of pneumoconiosis

• The two diseases modify each other and numerous round opacities up to 5 cm in diameter, resembling metastases, may appear

• The solid fibrotic lesions eventually become hyalinised and may calcify

105

106Rheumatoid disease, cavitating necrotic nodules

2.23.Wegener’s granulomatosis

• A necrotising vasculitis, involves the upper respiratory tract, the lungs and the kidneys

• A limited variant, confined to the thorax

• Symptoms referable to the upper air passages almost always present

107

2.23.Wegener’s granulomatosis

• Cough, haemoptysis and pleurisy accompanied by constitutional symptoms of malaise, weakness and fever

• Rheumatoid and antinuclear factors are commonly found in the blood

• Inflammatory necrosis in the walls of small arteries and veins leading to occlusion of lumen

108

2.23.Wegener’s granulomatosis

• Granulation tissue represents a reparative process- undergoes necrosis

• Necrotic granulation tissue forms rubbery pulmonary masses, which may be single or multiple up to several centimetres in diam, fairly well defined and often cavitate: they may resolve spontaneously, while new masses appear

109

2.23.Wegener’s granulomatosis

• Cavitating lesions may have thick or thin walls, depending on how much of the necrotic material is expectorated

• Multiple cavities can closely mimic tuberculosis

110

111Wegener's granulomatosis pulmonary masses

112Wegener's Granulomatosis, cavitating masses

113

2.6. Diaphragmatic hernia

2.9.Hydropneumothorax

• A pneumothorax containing a horizontal fluid level which separates opaque fluid below from Iucent air above

114

115Loculated pyo-pneumothorax

116

Empyema

Abscess Empyema

Shape Round/ oval Oval/ lenticular/ crescentic

Angles with pleural surface

Acute Obtuse

Wall Irregular, thick Smooth, regular

Pulm vessel/ bronchi

entering wall/ center

displaced

117

118