SOLITARY PULMONARY NODULE

DR.BHARAT SINGH DMRD-1ST YEAR

SNMC AGRA

DEFINITION A solitary pulmonary nodule

(SPN) is a round or oval opacity smaller than 3 cm in diameter that is completely surrounded by pulmonary parenchyma and is not associated with lymphadenopathy, atelectasis, or pneumonia.

INCIDENCE SPN is found in 1-2% of all CXR

Geographic variations in the incidence of benign lesions, especially infectious granulomas

No sex difference in incidence

Solitary nodules can occur at all age

CONTI…. Smoking history Prior history of malignancy Travel history - Travel to areas with endemic

mycosis (eg, histoplasmosis, coccidioidomycosis, blastomycosis) or a high prevalence of tuberculosis

Occupational risk factors for malignancy - Exposure to asbestos, radon, nickel, chromium, vinyl chloride, and polycyclic hydrocarbons

Previous history of tuberculosis or pulmonary mycosis

ETIOLOGYCongenital TraumaticBronchogenic cysts hematomaAVM (congenital arteriovenous malformations)Bronchial atresia

Infective NeoplasticTB, round pneumonia Bronchogenic ca. Fungal CarcinoidHydatid PlasmacytomaAbscess MetastasesMiscellaneous Lymphoma Wegeners granulomatosis Adenoma, hamartomaRAAmyloidosis ARTEFACTSRounded atelectasis

SPN - ETIOLOGY 40% of spn are malignant, with other common

lesion being granuloma and benign lesion Benign

80% infectious granulomas10% hamartoma10% non-infectious granulomas, benign

tumours Malignant

25% metastatic75% bronchogenic carcinoma and carcinoid

SIMULANTS OF SPNExtra thoracic artefacts

Cutaneous masses – nipple, lipoma ,NF Bony lesions – island, healing #, sclerotic lesion Pleural tumors / plaques Encysted pleural effusion Pulmonary vessels

MODALITIES USED

PLAIN radiography CT

NCCT, CECT PET WITH FDG-F18 PET- CT FNAC / BIOPSY

TWO ISSUES

Lesion detection

Lesion characterization benign versus malignant

LESION DETECTED ON CHEST XRAY Pick up depends upon experience Over reading/ under reading High Kv – better rate of detection Digital radiographs- allow manipulation on a computer

monitor

Always compare current radiographswith previous radiographs

LESION DETECTED ON CXR

SPNs are discovered first as incidental findings on chest radiographs

The first step is to determine whether the nodule is

pulmonary or extra pulmonary

A lateral chest radiograph, fluoroscopy, or CT of the chest

often helps determine the location of the nodule

>8-10 mm Nodules are identifiable by chest radiographs

Occasionally, SPNs can be visualized at 5 mm in diameter

INTERNAL CHARACTERISTICS

Size

Margin

Calcification

Fat

Cavitation

Air bronchograms or bubbly lucencies

SIZEThe size of the mass is of little diagnostic

valueOnly a small percentage of nodules under 1 cm in diameter are malignent.

MARGIN Small nodule with smooth margin suggestive of benign

but not diagnostic of benign lesionLobulated contour Irregular margin typical malignant lesionSpiculating margin

Adjacent tiny nodules, called satellite nodules, may mimic the appearance of a lobulated and the presence of these nodules is strongly associated with benign nature

SMOOTH MARGIN - BENIGN

CALCIFICATION Suggestive of benign SPN

– Central, solid

– Laminated

– Popcorn -1/3 rd of hamartoma

– Diffuse

Suggestive of Malignant SPN

– 6-14% of malignant nodules are calcified on CT

– Eccentric

– Stippled

SOLITARY PULMONARY NODULECALCIFICATION

A stippled appearance or psammomatous calcification

can be seen in SPNs that are metastases from mucin-

secreting tumours such as colon or ovarian cancers

• Dense foci of calcification or be entirely calcified,

with a pattern resembling that of benign Disease can be

seen in carcinoid, metastatic osteosarcoma and

chondrosarcoma

PATTERN OF CALCIFICATIONCentral = granuloma

Nodule completely calcified = granuloma

Target = histoplasmosis

Popcorn = hamartoma

ECCENTRIC CALCIFICATION

ECCEN

CENTRAL CALCIFICATION

CAVITATION

SPNs with irregular-walled cavities thicker than 16 mm tend to

be malignant

Benign cavitated lesions usually have thinner, smooth wall

Up to 15% of lung cancers form a cavity, but most are larger

than 3cm in diameter

THICK WALLED THIN WALLED

AIR BRONCHOGRAM Air bronchograms are seen more commonly in

pulmonary carcinoma than in benign nodules

Air bronchograms were seen in approximately

30% of malignant nodules but in only 6% of

benign nodules

Air bronchograms is due to desmoplastic reaction

to the tumour that distort the airway

HAMARTOMA

50% of hamartomas have fat

30% of hamartomas have calcification (popcorn appearance)

Middle-aged adults, slow growth ,90% in intra pulmonary

and within 2cm of pleura

fat is present in the nodule , hamartoma or lipoma become

most likely cause , Metastasis from lipo sarcoma, RCC, may

occasionally contain fat

In patient without prior malignancy, focal attenuation

(-40to-120) is reliable indicator of hamrtoma.

HAMARTOMA

INFECTION tuberculoma:

most common in upper lobe

well defined and lobulated ,

calcification frequent , 80% have satellite leison

Cavitation is uncomman

Histoplasmosis

Most frequent in lower lobe

Well defined / seldom larger than 3cm

Calcification common and central –target appearance

Cavitation are rare

HYADIT CYST

Most common right lower lobe

Common in endemic area

Well defined , 1-10 cm in size

Rupture result in –water lilly sign

VASCULAR AVM: Well defined and lobulated- Bag of worm appearence dilated feeding arteries and draining vein may be visible 66% are single, calcification is rare Hematoma peripheral ,smooth and well defined slow resolution over several weeks Pulmonary infarction Most frequent in lower lobe wedge shaped area of consolidation can be identified abutting the

pleura , small u/l or b/l pleural effusion is seen

AVM

AVM WITH FEEDING VESSELS

CONGENITAL Pulmonary sequestration

usually more than 6cm in diameter 2/3rd in left LL ,1/3rd in rt LL well defined round or oval lesion Confirmed by aortography and venous drainage is via

pulmonary vein or bronchial vein

Bronchogenic cyst well defined, round or oval in shaped ,smooth wall 2/3rd are intrapulmonary , located medial 1/3rd of LL Peak incidence in 2nd and 3rd decade of life

CT SCAN

standard CT examination without contrast material enhancement may be performed

Ensure there are no other findings, such as additional nodules lymphadenopathy, pleural effusion, chest wall involvement, or adrenal mass.

concerns about radiation dose to the patient, subsequent follow-up CT may be limited to the nodule location.

CT CON… Thin-section CT scans obtained through the nodule

provide information regarding nodule size (by using diameters from the largest cross-sectional area or volume measurement) attenuation, edge characteristics, and the presence of calcification,cavitation, or fat .

Sequential thin-section CT (1 3-mm section width) performed through the entire nodule with a single breath hold and without contrast

GROWTH RATE ASSESMENT Absence of detectable growth over a 2-year period of

is a reliable criterion for establishing that a pulmonary nodule is benign

Difficult to detect growth in small (< 1cm) nodules. To overcome this limitation,

growth rate of small nodules be assessed using serial volume measurements rather than diameter

Computer-aided 3D quantitative volume measurement methods have been developed and applied clinically

All these volumetric methods are focused on solid pulmonary nodule

DOUBLING TIME

Volume is doubled if diameter has increased by at least 1.25 times in at least 2 dimension

Usally malignant lesions have a doubling time of 1-6 months.

Masses are considered benign when they have not change in size for 18 months

many lesions are not completely spherical Hemorrhage into a lesion can increase the volume

dramatically bronchial carcinoids and BAC long doubling times

DYNAMIC –HELICAL CT The lesion should be at least 10mm

Contrast enhancement is directly related to the

vascularity and blood flow

Nodule examined 3mm collimation before and after

administration of contrast

1min interval up to 4min after administration of contrast

Nodule enhancement= peak mean – base line

attenuation

CON… Early cut of point for differention of benign from

malignant nodule - 15H enhancement

Early study more focus on early phase of dynamic

CT .this studies are more sensitive but less specific

Overlap was found between malignant and benign

nodules for example, active granulomas and benign

vascular tumours

CON… FALSE POSITIVE: active infection active inflammation FALSE NEGATIVE Broncho alveolar ca Lesion with central necrosis cavitatory lesion

MRI Special circumstances – contrast allergy etc

Not routinely used due to cost factor

CT is as good

TISSUE DIAGNOSIS

TTNA-TRANS THORACIC NEEDLE

ASPIRATION

24 G needle

CORE BIOPSY

BRONCHOSCOPIC BIOPSY

TRANS THORACIC NEEDLE BIOPSY (TTNB) indication

FNAB can be used to diagnose malignancy and determine the histologic type of malignancy. In patients who are candidates for surgery

FNAB may be used to diagnose benign disease, thus obviating surgery

Contraindications inability of the patient to cooperate Other relative contraindications bleeding diathesis, previous pneumonectomy, severe emphysema, severe hypoxemia, pulmonary artery hypertension, nodules which successful biopsy cannot be performed

TTNB...

Nodules that are in the lower lobes or adjacent to the

heart may be difficult to access because of varying

breath holds and diaphragmatic and cardiac motion

TTNB... When the FNAB sample is interpreted as malignant or

specific benign condition is, further workup based on

diagnosis.

when a nonspecific benign condition is diagnosed,

further evaluation is required

The most common complications of

FNAB are pneumothorax and hemorrhage

PET with FDG-F18

PET-CT may be selectively performed to characterize SPNs when dynamic helical CT shows inconsistent results between morphological and , hemodynamic characteristics

PET 18F-FDG is accurate ,noninvasive diagnostic test PET-CT provide more anatomical detail than PET alone

or CT alone Increased uptake of 18F-FDG –MALIGNANT Decreased uptake - BENIGN False positive- infection /inflammation False negative –BAC, carcinoid Best test for lesion >1cm lesion

SPN IN RT LOWER LOBE IN CT, SHOWING INCREASED UPTAKE ON PET- ADENOCARCINOMA

CLINICAL BENIGN MALIGNANTAge < 35 yrs >35 yrsh/o smoking - +

Exposure to TB

+ -

Exposure to carcinogens

- +

Primary lesion elsewhere

- +

Chest X ray BENIGN MALIGNANT

size < 3cm >3 cmlocation Not specific Upper lobesmargins smooth Spiculatedcalcification Central,

diffuse, laminated, popcorn

Eccentric/ stippled

Growth pattern Stable for 2 yrs Presence of growth

Satellite nodule more less

CT BENIGN MALIGNANT

Fat + -

Bubble like lucencies

uncommon Common

Enhancement < 25 HU > 25HU

densitometry > 200 HU < 200 HU

DIAGNOSTIC CRITERIAINDICATED A MALIGNANT NODULE

≥ 25 H wash-in and 5–31 H washout

lobulated margin

spiculated margin

absence of a satellite nodule

SUMMARY OF RECOMMENDATIONS FOR FOLLOW-UP ANDMANAGEMENT OF INCIDENTAL SMALL (< 8MM) NODULES DETECTED ON NON-SCREENING CT SCANS

NODULE SIZE IN MM

LOW RISK PATIENT HIGH RISK PATIENTT

<4MM NO FOLLOWUP NEEDED IN ITIAL CT AT 12 MONTH, IF UNCHANGED, NO FOLLOWUP

4-6MM IN ITIAL CT AT 12 MONTH, IF UNCHANGED, NO FOLLOWUP

INITIAL CT AT 6TO12 MONTH THEN AT 18 -24 MON IF NO CHANGE

6-8 MM INITIAL CT AT 6TO12 MONTH THEN AT 18 -24 MON IF NO CHANGE

INITIAL CT AT 3 TO 6 MONTH THEN AT 9 TO 12 MON AND 24MON IF NO CHANGE

>8MM CT FOLLOWUP 3, 9, 24 MON/DYNAMICCT/PET CT/BIOPSY

CT FOLLOWUP 3, 9, 24 MON/DYNAMICCT/PET CT/BIOPSY

MacMahon, H. et al. Guidelines for management of small pulmonary nodules detected on CT scans:A statement from the Fleischner Society. Radiology 2005; 237: 395-400

DO not use in pts <35y/o; h/o malignancy or in pts w fever.

CONCLUSION CT screening, has increased the detection rate of small nodular

lesions,

In providing information about morphological and hemodynamic

characteristics with high specificity and reasonably high accuracy,

CT scan can be used for the initial assessment of SPNs.

PET-CT is more sensitive for detecting malignancy than dynamic

helical CT, and all malignant nodules may be potentially diagnosed

as malignant by these two techniques.

PET-CT may be selectively performed to

characterize SPNs when dynamic helical CT shows

inconsistent results between morphological and

hemodynamic characteristics

Serial volume measurements are currently the most

reliable methods for the tissue characterization of

subcentimeteric nodule

THANK YOU