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WORK UP & MANAGEMENT OFSOLITARY PULMONARY NODULE
Seifu B
Oct-04, 2007
Introduction
• SPN or ‘Coin’ lesion- common• Detected incidentally-0.09 to 0.2%
CXR• Major ? To R/O Malignancy
Defn ; an approximately round lesion, <3cm in diameter, surrounded by normal aerated lung without other abnormality
Etiologies of SPN
Numerous causesMalignant Vs BenignVariable frequency
Carcinoid tumors
Malignant Etiologies
Incidence of Ca –range from 10-70%
Primary Lung Ca• All types• Most common as SPN= Adenocarcinoma→
Squamous cell ca → Large cell Ca
Carcinoid tomors• Central, endobronchial• 20% arise peripherally, as SPN
Metastatic Ca• Commonly as multiple• As SPN; Melanoma, Sarcoma, Colon
Ca, Breast, Kidney, Testes• Extra thoracic malignancy + SPN-
25% probability
Benign Etiologies
Infectious Granulomas• Cause of 80% of benign lesionsMost frequent• Endemic fungi• MycobacterialHamartomas• 10% benign nodules• Xic CXR & CT findings
General Approach to SPN
Ideal Resection of all malignant nodulesAvoiding resection of all benign onesImplementation = difficultDifferent approaches exist
Initial diagnostic evaluation
Determination of probability of malignancy
→ Selection of managementBased on:Clinical featuresRadiologic featuresQuantitative models
Clinical features Probability of malignancy increased
with1. Advanced age
One study: 3% in patients b/n 35 & 39, 50% in those > 50 yrs of age
2. Presence of risk factors Smoking!!! Asbestos exposure Family history Diagnosed malignancy
Radiologic features
CXR- being replaced with CTFeatures used:
SizeBorderCalcificationDensityGrowth rateMetabolic activity
Radiologic features…
Size • Any size –considered malignant until
proven otherwise• >3cm- more likely to be malignant-
80 t0 90 %
Calcification • Suggestive of benign• Does not rule out malignancyPattern more important
Patterns of calcification
Suggestive of benign
Diffuse homogenous
Central ConcentricPopcorn
Of malignancyReticularPunctateAmorphousEccentric
Radiologic features…
Attenuation • Measure of electron density-
Hounsfield units• Increased density- Benign• Not used routinely
Radiologic features…
Border Likelihood of malignancySmooth- 20%Scalloped- 60%Spiculated- 90%Corona radiata- 95%
Bron ca,Hamar, Carci, Pul inf
Radiologic features…
Growth rate• Review of old X-rays!• Malignancy doubling time-20 to
400daysVery rapid, or slow- less likely to be
malignant• Stability on CXR for 2 yrs- benign ?• Several pitfalls• CT- preferred
Radiologic features…
Other helpful signs:MorphologyWall thickness of cavitating nodulesNodules with tails towards the hilum
Radiologic features…
Metabolic imagingFDG-PET• More accurate than CT• Ix- SPN> 1cm & intermediate
probability of malignancy• Sensitivity & Specificity- 96 & 78%• Detection of metastasis- staging• False positive & negative results
Quantitative Models
• Use likelihood ratios to estimate the probability that a SPN is malignant
• Based on clinical & radiologic characteristics
Nodule Sampling
If no sufficient evidence• Different options- based on size,
location & availabilityBronchoscopyNeedle aspirationNeedle biopsySurgical resection
Initial Management
• Decision made after initial assessment
• Various approaches• Individualized based on:Pretest probability of cancerCost effectivenessPatient preference
Initial Management…
One approachWhen probability of cancer is Low (< 12%)- Radiologic follow upIntermediate(12-69%)- CT & PETHigh (69-90%)- CT followed by biopsy
or surgeryVery High (>90%)-Surgery
References • Harrison's Prin. Of Int. Med 16th Edition
• Up To Date 15.2
• NEJM-2003: 348
• Granger's Diagnostic Radiology
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