Solitary pulmonary nodule

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SOLITARY PULMONARY NODULE

Solitary pulmonary nodule AN UPDATE ON IMAGINGDr . ARUN KUMAR

1 DEFINITIONRound or oval opacity smaller than 3 cms in diameterCompletely surrounded by lung parenchymaNo atelectasisNo lymphadenopathyNo pneumonia Lesions more than 3cms are termed as masses. SPN MASS

CLASSIFICATION ON CTSolid-Soft tissue attennuationSub solid-Ground glass attenuation Soft tissue with ground glass attenuation DIFFERENTIAL DIAGNOSIS FOR SOLID SPNS

CAUSECONDITION Neoplastic (malignant)Primary lung malignancies (nonsmall cell, small cell, carcinoid, lymphoma), solitary metastasis Benign Hamartoma, arteriovenous malformation Infectious Granuloma, round pneumonia, abscess, septic embolus Noninfectious Amyloidoma, subpleural lymph nodule, rheumatoid nodule, Wegener granulomatosis, focal scarring, infarct Congenital Sequestration, bronchogenic cyst, bronchial atresia with mucoid impaction SUB SOLID SPNTYPE OF CAUSE

CONDITION

Malignant

LUNG ADENOCARCINOMA;Metastasis from melanoma, renal cell carcinoma, and Adenocarcinoma of the pancreas, breast, and gastrointestinal tract Lymphoproliferative disorders

Benign

Organizing pneumonia,Focal interstitial fibrosis, Endometriosis

EVALUATIONClinicalRadiological

CLINICAL EVALUATIONHistory of smoking, Age over 40,Occupational exposures (e.g., asbestos),Lung fibrosis, Coexisting chronic obstructive pulmonary disease (COPD) and emphysema,Family history of lung cancerRecent travel history,Positive skin test for tuberculosis (TB) or fungus, or Presence of other diseases (e.g., rheumatoid arthritis) RADIOLOGICAL EVALUATIONChest x rayCT scanFDG-PETBIOPSYNewer modalities-Dynamic MR imaging DW MRIFOLLOW UP MORPHOLOGICAL EVALUATION SizeLocationEdge AppearanceCalcification AttenuationAir Bronchograms and PseudocavitationCavitationSatellite NodulesFeeding Vessel Sign

11FatWater DensityContrast EnhancementHemodynamics Growth SIZE The smaller the nodule the more likely it is benign. Limited use in sub solid SPN Size (cm) LikelihoodRatio 3.0 5.23 2.13.0 3.67 1.12.0 0.74 1.0 0.52 SIZE INTERPRETATION < 3mm99.8% benign 4-7mm99.1%benign 8-20mm82%benign >20mm50%benign >30mm7%benign LOCATION Attached nodule length of contact surface of nodule >50% of nodule diameter or major part of non spherical nodule is attached to fissure /pleura/vessel implies benignity. BENIGN-Evenly distributed through lung MALIGNANT-R>L;UL>LL Adenocarcinomas Peripheral Small cell carcinomas- Central Metastasis- Peripheral/sub pleural Associated with fibrosis- Lower lobes EDGEBenign lesions - smooth, sharply defined edge .Malignant nodules -ill-defined, irregular, lobulated, or spiculated margin(corona radiate and corona maligna )SHARPLY MARGINATED Granuloma Hamartoma or benign tumor CARCINOID TUMOR METASTASISSpiculated (corona radiata) growth of cells along interstitum Bronchioloalveolar carcinoma GRANULOMA OR FOCAL SCARRING

Hamartoma presenting as a sharply defined, round nodule. A. Chest radiograph shows a round nodule (arrows) in the right upper lobe. B. CT shows the nodule (arrow) to be rounded in shape and sharply marginated. Slight lobulation may be seen with hamartomas

Solitary metastasis from a head and neck carcinoma. A left upper lobe nodule (arrow) is smooth and sharply defined on CT. This appearance is common with metastases.

Adenocarcinoma. HRCT shows an irregular, spiculated nodule with multiple pleural tails. Air bronchograms are visible within the nodulePLEURAL TAIL SIGN-linear opacity is seen extending from the edge of a lung nodule to the pleural surfaceCT HALO SIGN-halo of GGO surrounding a nodule.Represents hemorrhage,inflammation,infiltration Fungi: invasive aspergillosis, candidiasis, coccidioidomycosis Bacteria: tuberculosis, Nocardia, Legionella Viruses: cytomegalovirus, herpes Pneumocystis jiroveci (P. carinii) Bronchiolitis obliterans with organizing pneumonia Wegener's granulomatosis Infarct Metastatic tumor-angiosarcoma,choriocarcinoma,osteosarcoma Kaposi's sarcoma

Halo sign a) invasive aspergillosis. HRCT in a young patient with leukemia and granulocytopenia shows a dense left lower lobe nodule surrounded by a halo (arrows) of ground-glass opacity. In patients with invasive aspergillosis, the halo represent hemorrhage surrounding a septic infarction b) bronchioloalveolar carcinoma, the halo represents the presence of lepidic tumor growthabReverse halo sign-ATOLL SIGN central area of ground glass attenuation surrounded by a halo or crescent of consolidationSeen in CRYPTOGENIC ORGANIZING PNEUMONIA Paracoccidioidomycosis, Tuberculosis, Lymphomatoid granulomatosis, Wegener granulomatosis, Sarcoidosis Lung cancer after radiotherapy

Reverse halo sign after radiofrequency ablation of a pulmonary metastasis in a 63 year-old man with pancreatic cancer who previously underwent left upper lobectomy. (a) CE CT image shows a left-lower-lobe metastasis (arrow). (b) CECT image obtained 1 month after radiofrequency ablation shows the treated metastasis (arrow), which now has mixed attenuation, surrounded by a ground glass opacity (*) and a well-circumscribed rim of consolidation (arrowheads) CALCIFICATION Most important characteristic feature Best detected on HRCT The presence of calcium in an SPN increases its chances of being benign Benign Indeterminate

BENIGN PATTERNHomogeneous calcification Dense central (bull's-eye) Concentric rings of calcium (target)Conglomerate foci of calcification involving a large part of the nodule (popcorn)

CARCINOID TUMOR MUCINOUS ADENOCARCINOMA. METASTASES FROM OSTEOGENIC SARCOMA OR CHONDROSARCOMA

a)Homogeneous calcification. Dense and uniform calcification of a small right upper lobe nodule (arrow) is typical of a benign lesion, usually a tuberculoma

b)Concentric or target calcification (arrow). One or more rings of calcium may be seen. This pattern is typical of a histoplasmomaba

a)Dense central or bull's-eye (arrows) .This is typical of histoplasmoma or hamartoma

b)Multiple confluent nodular foci of calcification (popcorn calcification; arrow) This appearance is typical of hamartoma and corresponds to calcification of cartilage nodulesab INDETERMINATE PATTERNStippledEccentricAmorphous

Eccentric calcification in an adenocarcinoma. A lobulated mass shows a small focus of eccentric calcification (arrow).Dual-energy CT, in which 80- and 140-kV images are simultaneously obtained, measurement of CT attenuation values obtained at different kilovolt peaks may be used to identify areas of calcium and iodinated contrast material. A multicenter trial showed that the use of unenhanced dual-energy CT to evaluate changes in attenuation values at 140 and 80 kVp is not reliable for differentiating benign and malignant nodules with 3-mm sections and differing acquisitions for both kilovolt potentials ATTENUATIONSoft tissue attenuation in solid SPNGGAN , GGAN + Soft tissue attenuation in sub solid SPNClassification of Nonmucinous Forms of Lung Adenocarcinoma & CT Features of Subsolid Nodules(2011 IASLC,ATS&ERS ) Atypical adenomatous hyperplasia GGAN Adenocarcinoma in situ GGAN with a possible solid component Minimally invasive adenocarcinoma GGAN, partly solid nodule Lepidic-predominant adenocarcinoma Partly solid nodule, solid nodule Invasive adenocarcinoma Partly solid nodule, solid nodule

Mean nodule attenuation number could be used to differentiate among AAH (-609 HU), BAC (-450 HU), and invasive adenocarcinomas (-319 HU). Although there is currently no standard CT methodology for quantifying the soft-tissue component of SSNs, direct correlation of the soft-tissue component with the degree of invasion or aggressiveness of subsolid adenocarcinomas and patient prognosis and survival has been reported Honda et al (45) reported that a ratio of the largest tumor dimension on images obtained with soft-tissue window settings versus that on images obtained with lung window settings of 50% or less indicated an air-containing type,(AIS) a ratio of more than 50% indicated a solid type lesion(INVASIVE ADENOCARCINOMAS) AIR BRONCHOGRAM & PSEUDOCAVITATIONPresence implies malignancy.Most typical of adenocarcinoma or bronchioloalveolar carcinoma.Small air-filled cystic areas in the tumor (so-called pseudocavitation), or small cavities have the same significance as air bronchograms.Other causes Conglomerate mass Focal pneumonia Infarction Rounded atelectasis Bronchiolitis obliterans with organizing pneumonia Lymphoma Lymphoproliferative diseases Mycetoma (may mimic a b