Congenital Lung Malformations: Radiologic-Pathologic Correlation

Transcription

1 Acta Radiológica Portuguesa, Vol.XVIII, nº 70, pág , Abr.-Jun., 2006 Congenital Lung Malformations: Radiologic-Pathologic Correlation Marilyn J. Siegel Mallinckrodt Institute of Radiology, Washington University School of Medicine, ST. Louis Distinguished Scientist, Armed Forces Institute of Pathology Learning Objectives Review clinical & pathologic features of common lung anomalies Describe imaging appearances of the common congenital anomalies Emphasize imaging differential diagnosis Congenital Lobar Emphysema Pathologic Features Bronchioles normal Alveolar distended 5-10X normal Sponge-like mass, fails to deflate on resection Compressed normal lung deflates & reexpands Congenital Lung Anomalies Normal vascularity Lobar emphysema Cystic adenomatoid malformation Bronchogenic cyst Bronchial atresia Parenchymal agenesis, hypoplasia Abnormal vascularity Scimitar syndrome Sequestration Arteriovenous malformation Lobar Emphysema: Imaging Lobar hyperinflation Atelectatic adjacent lung Mediastinal shift Attenuated vascularity Lobar predilection: LUL (50%), RML (24%), RUL (18%) Congential Lobar Emphysema Lobar overinflation Cause: bronchial obstruction deficiency of bronchial cartilage Onset: 50% 1st week, 90% < 6 months Neonates dyspnea, cyanosis, cough Later-asymptomatic, wheezing Lobar Emphysema Neonate with respiratory distress ARP 51

2 Companion Case 2-week-old boy with mild dyspnea CAM: Path Features Classification (Stocker) Type I: (50%) Large cyst(s) (> 2 cm) Type II: (40%) Multiple cysts (< 2 cm) Type III: (10%) Solid Congenital Lobar Emphysema Cystic Adenomatoid Malformation Bronchiole-like structures of varying sizes Usually diagnosed in neonates & infants 20 % diagnosed in adolescents & adults 18-year-old male wheezing Lobar Emphysema CCAM: Imaging Type I Air-filled, multicystic lesion Dominant cyst(s) Fluid-filled, air fluid levels Type II Heterogeneous, uniform small cysts Type III Large, homogeneous Resembles consolidation Echogenic on prenatal US Cystic Adenomatoid Malformation Type I CCAM: Large Cysts Neonate with dyspnea 25% of congenital lung lesions Mass of disorganized lung tissue Result of bronchiolar proliferation 70% present < 1 year, dyspnea Normal arterial supply Communicates with bronchial tree 52 ARP

3 Type II CCAM: Small Cysts Another Case: CAM 18-year-old male Spectrum of CCAM Another Case 10% diagnosed in adolescents & adults Infection common May mimic infiltrate or mass on imaging studies CCAM Antenatal Diagnosis Polyhydramnios Adolescent with cough ARP 53

4 Bronchogenic Cyst Bronchogenic Cyst Failure of lung bud to incorporate into primitive lung Lung or mediastinum Rare in infants, more common in children & adults Asymptomatic & incidental finding Symptomatic from mass effect 7- year-old girl with cough Bronchogenic Cyst: Path DDX: Cystic Adenomatoid Malformation Gross Separate from lung Round or ovoid Clear or turbid contents Histo Lined by respiratory epithelium Bronchial glands, cartilage, smooth muscle in wall Septations and multiple cysts favor CAM Pulmonary Bronchogenic Cyst: Imaging Smooth, rounded, solitary mass CT: nonenhancing mass Air-filled usually Air-fluid levels Wall calcification, rare Bronchial Atresia (Congenital Mucocele) Failure of bronchial bud to maintain communication with airway Wheezing, cough or incidental detection Imaging: nodular opacity»fluid-filled dilated bronchi surrounding emphysema (distal air drift) Companion Case 15-year-old boy, wheezing 54 ARP

5 Bronchial Atresia Arrested Pulmonary Development Agenesis: Complete absence of lung tissue, artery, & small or absent bronchus Hypoplasia: Small lung & bronchus (artery may or may not develop) Bronchial Atresia 2 month old, cough Pulmonary Agenesis Dilated mucus-filled bronchi & overinflated lung Bronchial Atresia Young adult, incidental finding Companion Case: Pulmonary Agenesis Nodular/tubular opacity & distal hypoattenuation Acquired vs Congenital Mucocele Arrested Pulmonary Development Pulmonary hypoplasia Small lung (hypoplasia) Small bronchus Absent or small pulmonary artery Acquired Congenital Distal air drift ARP 55

6 Pulmonary Hypoplasia 2-month-old boy, mild dyspnea Congenital Anomalies with Abnormal Vasculature Hypoplasia with anomalous venous return Scimitar syndrome Pulmonary sequestration Arteriovenous malformation Small lung & bronchus, No PA Pulmonary Hypoplasia Hypogenetic Lung Syndrome Form of pulmonary hypoplasia with PAPVR PAPVR into IVC, portal vein/ hepatic vein, or right atrium Often asymptomatic and discovered during evaluation of another anomaly Pulmonary Hypoplasia Hypogenetic Lung Syndrome 10 year old girl Pneumonia suspected 56 ARP

7 Hypogenetic Lung Syndrome Scimitar Syndrome Hypogenetic Lung Syndrome Pulmonary Sequestration No normal communication with tracheobronchial tree Systemic blood supply Extralobar sequestration Separate pleural investment Intralobar sequestration Shares pleura of parent lung ILS : ELS = 4 : 1 Companion Case Pulmonary Sequestration Young adult Chest pain ARP 57

8 Sequestration: Clinical Intralobar Sequestration Extralobar 60% present within 6 months Often asymptomatic Dyspnea, cyanosis occasionally Intralobar Symptomatic (> 50% by age 20) Cough, recurrent pneumonia Arterial feeder from lower thoracic aorta Intralobar Sequestration Intralobar sequestration Abscess Formation Path- edge may abruptly abut normal lung or blend with normal lung Shares pleura of normal lung Imaging infiltrate (pneumonia) mass abscess 6-year-old girl, fever and cough Intralobar Sequestration 6-month old, Recurring pneumonias Intralobar sequestration Intralobar Sequestration Extralobar Sequestration Path-separate from normal lung between lower lobe & diaphragm mediastinum abdomen Imaging Soft tissue mass 58 ARP

9 Extralobar Sequestration ELS with CCAM (40%) Newborn with in utero chest mass Extralobar Sequestration Arteriovenous Malformation 80% Hereditary telangiectasia (OWR) 15% sporadic 5% cardiac surgeries (Glenn or Fontan) Symptomatic in older patients (cyanosis, polycythemia, dyspnea) 80-90% are simple AVMs single feeding and draining vessel commonly lower lobes MPR/3D images >> axial for small oblique vessels Extralobar Sequestration Arteriovenous Malformation Sequestration Pulmonary AVM ARP 59

10 Simple Pulmonary AVM Multiple AVMs (35%) 7 yo girl: Abnormal Chest X-ray Congenital Lung Anomalies 60 ARP