Solitary pulmonary nodule

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  • 1.SOLITARY PULMONARY NODULE

2. INTRODUCTION Definition : Opacity with diameter < 3cm Larger lesions are called masses Completely surrounded by lung parenchyma It occurs in 1 every 500 CXR 3. Differential Diagnosis Neoplasm-----Malignant Ca bronchus,Metastasis,Alveolar cell, carcinoma,blastoma,sarcoma plasmacytoma. Benign---Carcinoid tumor, hamartoma Infection/Inflammation-----pneumonia ,hydatid,rounded atelactasis,sarcoidosis Vascular lesion-----haematoma,AV malformation 4. Pulmonary infarct Post-traumatic Congenital---> Sequestration, Bronchogenic cyst, Intrapulmunary lymph node Amyloidosis Rheumatoid nodules Plasma cell granulomas (tuberculoma,hist oplasmoma) Mucoid impaction Nipple shadow 5. Most lesions are found to be granulomas, lung cancers, or hamartomas 6. Basic strategy is to identify malignant versus benign 7. Factors in determining malignancy Calcification Growth Location Size Margin Cavitation 8. RISK OF SPN MALIGNANCY 9. In patients with melanoma, sarcoma, or testicular carcinoma, a malignant SPN is 2.5 times more likely to be a metastasis than a primary lung cancer However, in patients with head and neck squamous cell carcinoma, a malignant SPN is 8 times more likely to be a primary lung cancer. 10. GROWTH OF A NODULE Benign lesions grow slowly with doubling time exceeding 500 days A doubling time of less than 20 days signifies inflammatory process Always compare the current radiographs with prior ones (if available) 11. Malignant nodules grow at a constant rate expressed as doubling time This usually falls between 25 and 450 days with a median of 120 days An increase of 28% in nodule diameter indicates doubling 12. 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 26 days. FNAB revealed mixed small cell and nonsmall cell carcinoma. 13. SPN LOCATION 14. In patients with idiopathic fibrosis, lung cancers more commonly involve periphery of lower lobe Benign nodules: Both upper and lower lobes 15. The right upper lobe is the most common location of lung cancer 16. HIGH RESOLUTION CT HRCT is the most sensitive and specific for assessing the size, shape, calcification and edge of a nodule Type 1 Type 2 Type 3 Type 4 17. Patterns of Margins Corona radiata sign Fine linear strands extending 4-5 mm outward Spiculated on CXRs 84 90% are malignant 18. Scalloped border Intermediate probability of cancer Smooth border suggestive of benign diagnosis 19. AIR BRONCHOGRAMS Air bronchograms and pseudocavitation more commonly malignant Cavitation with thick (>15 mm vs. < 5 mm) more often malignant 20. CALCIFICATION Radiographic pattern of calcium deposition is helpful Benign lesions tend to have central, laminated (bulls eye), diffuse or popcorn pattern Malignant lesions have speckled or eccentric pattern 21. Calcification Laminated or central pattern typical of granuloma 22. Calcification Stippled or eccentric patterns Have been associated with cancer 23. Popcorn Calcification Classic popcorn pattern often seen in hamartomas HRCT can show fat and cartilage in half of cases 24. CAVITATION 25. TUBERCULOMA /HISTOPLASMOMA common in upper lobes and on the right side 0.5-4cm in size Calcification is diffuse/central Common in lower lobes 3cm or smaller Central calcification producing target appearance 26. HISTOPLASMOMA 27. CONTRAST ENHANCED CT Contrast-enhanced examinations are performed at 1- minute intervals up to 4 minutes after injection of contrast material Enhancement of less than 15 HU after administration of contrast material is strongly indicative of benignity (positive predictive value, approximately 99%). 28. False negatives: central noncavitating necrosis and adenocarcinomas (especially bronchioloalveolar cell carcinoma), which may be related to mucin production False positives: active inflammatory diseases e.g. organizing pneumonias and granulomas 29. In summary, behavior after contrast material administration is sensitive but not specific for malignancy 30. 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) 31. Uptake of Fluorine 18-flurodeoxyglucose used to measure glucose metabolism. Most tumors have greater uptake of FDG than normal tissue Helpful in detection of mediastinal lymph node mets, even when nodes are not enlarged on CT scans Occult extra thoracic mets and synchronous extra thoracic primary malignancies 32. FDG PET examination of an SPN larger than 1 cm in diameter is the best test to determine if a lesion is malignant or benign FDG PET scan: Lingular nodule (arrow) with SUV of more than 2.5. FNAB revealed carcinoid tumor 33. BIOPSY Transthorathic needle aspiration (NAB) has a sensitivity of 80% to 90%. Non specific benign include atypical bronchioloalveolar hyperplasia or inflammation without organisms on a smear or a culture . Careful clinical and radiographic follow-up: If further growth occurs, repeat biopsy or resection is indicated. 34. FNAB results other than a specific malignant or benign diagnosis should be viewed with caution 35. IMAGING MANAGEMENT OF INDETERMINATE NODULES 36. DECISION MAKING Review all prior CXR Get CT scans If probability of cancer is