Bronchopulmonary foregut malformation: A pictorial review.

Transcription

1 Bronchopulmonary foregut malformation: A pictorial review. Poster No.: C-1676 Congress: ECR 2013 Type: Educational Exhibit Authors: N. L. Eun, C. S. Yoon, M.-J. Lee, M.-J. Kim ; Rep. of KOREA/ KR, Seoul/KR Keywords: Education, Ultrasound, Digital radiography, CT, Respiratory system, Pediatric, Congenital DOI: /ecr2013/C-1676 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 24

2 Learning objectives To address embryology, radiologic findings and bronchopulmonary foregut malformation (BPFM). disease entities about Background I. Bronchopulmonary foregut malformation (BPFM) (Fig. 1) 1. Full spectrum of diseases that arise from embryonic foregut during the process of fetal lung development. 2. BPFM is rare; however, their presentation may be life-threatening and may require urgent diagnosis and surgical intervention. 3. Imaging plays a central role in the evaluation of BPFM because their symptoms are not specific. II. 5 phases of development of the lungs (Fig. 2) 1. Embryonic 1) 1-4 weeks: formation of the respiratory diverticulum (laryngotracheal bud) from the ventral wall of the primitive foregut 2) 5-7 weeks: the distal end of the laryngotracheal bud bifurcates into two lung buds that grow to form the right and left mainstem bronchi 2. Pseudograndular 7-16 weeks: the segmental and subsegmental bronchi, bronchioles, and each terminal bronchiole gives rise to a number of alveolar ducts and alveoli 3. Canalicular weeks: distal acinar unit develops and further airspaces are being canalized and approximated by a network of capillaries 4.Saccular Page 2 of 24

3 24-36 weeks: alveoli and terminal sacs continue to develop, with compression of intervening interstitium and the beginning of alveolar septation 5. Alveolar After 36 weeks- 2 years: the appearance of fully mature alveoli III. Specturms of BPFM (Fig. 3) 1. Foregut abnormalities 1) Bronchogenic cyst 2) Esophagial/Neuroentericcyst 3) Tracheoesophageal fistula/diverticula/stenosis 2. Airway abnormalities 1) Tracheal Atresia 2) Bronchial Atresia 3) Tracheal Bronchus 3. Parenchymal abnormalities 1) Pulmonary Agenesis/Hypoplasia 2) CLE 3) Pulmonary sequestration 4) CPAM 4. Vascular abnormalities 1) Pulmonary Sling 2) Alveolar Capillary Dysplasia 3) Pulmonay isomerism We want to briefly review diseases and imaging findings of BPFM focused on foregut, airway and parenchymal abnormalities. Page 3 of 24

4 Images for this section: Fig. 1: Common embryological origin of pulmonary and digestive system Page 4 of 24

5 Fig. 2: Principal malformations of the respiratory system Fig. 3: Spectrums of BPFM Page 5 of 24

6 Imaging findings OR Procedure details I. Foregut anomalies 1. Tracheoesophageal fistula (Fig 4, 5, 6, 7) 1) Failure of formation of the tubular esophagus and/or an abnormal communication between the esophagus and trachea. 2) Due to a developmental disorder in formation and separation of the primitive foregut into trachea and esophagus. 3) Esophageal ateresia(ea) can occur in presence or absence of TEF, rarely, TEF can occur without EA (H-type fistula). 4) 1:3,000 live births, sporadically. 5) 50-75% of those have associated anomalies -Musculoskeletal 14-24%, cardiovascular 11-49%, gastrointestinal 20%, genitourinary 12-50%, craniofacial 10%, neurologic 7%, pulmonary 2% -"VACTERL"complex (vertebral,anal,cardiovascular,tracheoesophageal, renal and limb malformations) 6) Radiologic findings - Chest radiography: a blind pouch of the proximal esophagus that is distended with air. - Radiographic evaluation should always include the abdomen to assess the presence of air in the gastrointestinal tract (distal fistula). Types A & B: Complete absence of gas in the stomach and intestinal tract. Types C and D: GI tract distended with air. - Atelectasis and pneumonia involving the upper right lobe are seen in up to 50% of cases. Page 6 of 24

7 - When type E (H-shaped tracheoesophageal fistula without atresia) is suspected, radiologic investigation is directed toward demonstration of the fistula, which typically courses forward and upward from the esophagus. Nonionic water-soluble contrast material is preferable in these patients, but a small amount of properly diluted barium can be used if necessary. 2. Esophageal duplication (Fig. 8, 9) 1) Second most common duplication of the gastrointestinal tract after ileal duplications. 2) The aberrant luminal recanalization theory: The foregut is covered by cells similar to those seen in the respiratory tract. It grows and obliterates the lumen and later produces secretions that form vacuoles, which line up longitudinally and eventually coalesce to form the new lumen. If some vacuoles fail to coalesce along the longitudinal axis, a cyst will form and become surrounded by the muscular layers. 3) Complete esophageal duplication is extremely rare: often associated with gastric duplication and with vertebral anomalies, esophageal atresia, and congenital diaphragmatic hernia. 4) Radiologic findings -Plain radiographs: posterior mediastinal masses of varying size. -Esophagoaphy: either the esophagus displaced to the side opposite the mass or an intra- or extramural mass. -RI: helpful in demonstrating the location and extent of cyst and to evaluate associated anomalies. -CT: sharply marginated and homogeneous near-water attenuation -MRI: T1WI = low signal intensity, T2WI = very high signal intensity Page 7 of 24

8 -Ultrasonography: limited in the evaluation of Transoesophageal US may be helpful in some patients. esophageal duplications. 3. Bronchogenic cyst (Fig. 10, 11) 1) Abnormal budding or bifurcation of trachea or bronchi before normal bronchus development from foregut. 2) Respiratory epithelium and cartilage with serous or mucous secretion. 3) Located in mediastinal (80%, subcarina or paratracheal) or parenchymal area (20%, medial 1/3). 4) Radiologic findings -Well marginated homogeneous round or oval mass, thin-walled air-filled cyst, air-fluid level (infected). -CT: homogeneous fluid-filled cyst (>HU 20), occasionally calcification, infection. Communication with bronchus showing air-fluid level within cyst. -MRI: T1WI= variable signal intensity, T2WI: high signal intensity II. Airway anomalies 1. Tracheal agenesis (Fig. 12, 13) 1) One of the rarest of tracheal anomalies 2) Diagnosed immediately after birth, based on clinical signs as cyanosis, severe respiratory distress, absence of audible crying and difficult/impossible intubation 3) VACTERL association 4) The classification of Floyd and colleagues Page 8 of 24

9 -Type I: a short segment of distal trachea arises from the anterior wall of the esophagus before dividing into the mainstem bronchi -Type II: complete agenesis of the trachea with a fistula between the esophagus and carina from which the two mainstem bronchi originate (most common) -Type III: bronchi arise individually from the anterior esophageal wall 5) Radiologic findings -Barium esophagogrphy: Fistula from esophagus to trachea can be found. -MDCT is the first choice! 2. Bronchial atresia (Fig. 14, 15) 1) Rare anomaly resulting from focal obliteration of a segmental, subsegmental, or lobar bronchus. 2) The bronchi distal to the stenosis are dilated and filled with mucus, with mild hyperinflation of the adjacent lung due to collateral air drift. 3) Radiologic findings -Prenatal U/S: the fluid-filled lung just distal to the atresia will be seen as an echogenic area that is indistinguishable from other congenital lung masses. -Fetal MR imaging: a focal lung mass with homogeneously high signal intensity on T2WI and the impacted mucus in the bronchus. -CT: mucus-filled bronchus near the hilum, as well as surrounding areas of air trapping. 3. Esophageal bronchus (Fig. 16, 17) 1) Esophageal lung Page 9 of 24

10 -Extremely rare type of bronchopulmonary foregut malformation where a main stem bronchus, usually the right bronchus is abnormally connected to the esophagus instead of the trachea -More severe malformation of tracheal agenesis with the bronchi arising separately from the esophagus -Involved lung is usually hypoplastic and frequently unilobar. -Many associated with TEF (EA/TEF) and cardiac anomalies (patent ductus arteriosus, dextroversion, etc.) 2) Esophageal bronchus -Segmental bronchus communicating to the lower esophagus -Milder cases of esophageal lung 4. Tracheobronchial remanant of the esophagus (Fig. 18) 1) Abnormal presence of a ring of tracheal cartilage in the wall of the esophagus and is an uncommon cause of congenital esophageal stenosis in children. 2) Contains respiratory epithelium, bronchial glands, cartilage and lymphatic tissue in the submucosa or muscularis propria, and occur in the abdominal portion of the esophagus. 3) In association with esophageal stenosis and tracheoesophageal fistulas. 4) Radiologic findings -Barium esophagography: the presence of esophageal stricture at the lower end of the esophagus just above the diaphragm and demonstrated a malabsorption pattern consistent with celiac disease. III. Parenchymal anomalies 1. Pulmonary sequestration (Fig. 19, 20, 21) Page 10 of 24

11 1) The second most common lung anomaly (after CPAM) detected antenatally. 2) A portion of lung that does not connect to the tracheobronchial tree and has a systemic arterial supply, usually from the thoracic or abdominal aorta. 3) Left lower lobe > Right Lower lobe. 4) Arise from a supernumerary lung bud caudad to the normal lung bud. 5) 2 types -Intralobar (Fig. 19) : shares the pleural investment with the normal lung and usually drains into the pulmonary venous system Diagnosed later in childhood and adulthood Controversy over the cause of intralobar type Repeated lung inflammation could cause small, normally present systemic pulmonary ligament vessels to hypertrophy, producing an acquired intralobar sequestration. -Extralobar (Fig. 20, 21) : has its own pleural investment and systemic venous drainage Associated anomalies : congenital diaphragmatic hernia, cardiac abnormalities, pulmonary hypoplasia, or foregut duplication cysts. - It may be located below the diaphragm and may mimic a neuroblastoma or adrenal hemorrhage. - Diagnosed in the prenatal-neonatal period. 6) Radiologic findings -Prenatal US: extralobar pulmonary sequestration as a homogeneous hyperechoic mass in a paraspinal location, most often the left lower thorax and the feeding artery originating from the descending aorta at color doppler. Page 11 of 24

12 -Prenatal MR imaging: a solid, well-defined, uniformly hyperintense mass on T2-weighted images and the feeding artery. -Hybrid lesions demonstrating imaging and pathologic features of both sequestration and CPAMs (particularly small cyst CPAMs) can occur. -Postnatal CT: feeding artery and abnormal venous drainage -On postnatal radiographs: these lesions are seen as soft-tissue masses with a smooth or lobulated contour, generally in the lung bases. 2. Congenital pulmonary airway malformation (CPAM) (Fig. 22, 23) 1) Heterogeneous group of cystic and noncystic lung lesions that largely result from early airway maldevelopment. 2) A result of bronchial overgrowth with almost complete supression of alveolar development. 3) Classification by Stocker -Type I: macroscopic cysts, at least larger than 2cm and lined with mucine secreting epithelium, and can contain cartilage (Fig. 23). -Type II: smaller than 1cm, lined by ciliated columnar epithelium. -Type III: solid-like content with a multiplicity of bronchial membranes and bronchioleresembling histology without cartilage content (Fig. 21). Images for this section: Page 12 of 24

13 Fig. 4: Classification scheme for tracheoesophageal fistula Fig. 5: A case of tracheoesophageal fistula type C (1) Page 13 of 24

14 Fig. 6: A case of tracheoesophageal fistula type C (2) Fig. 7: A case of tracheoesophageal fistula type C (3) Page 14 of 24

15 Fig. 8: A case of esophageal duplication (1) Fig. 9: A case of esophageal duplication (2) Page 15 of 24

16 Fig. 10: A case of bronchogenic cyst (1) Fig. 11: A case of bronchogenic cyst (2) Page 16 of 24

17 Fig. 12: A case of tracheal agenesis (1) Fig. 13: A case of tracheal agenesis (2) Page 17 of 24

18 Fig. 14: A case of bronchial atresia (1) Fig. 15: A case of bronchial atresia (2) Page 18 of 24

19 Fig. 16: A case of esophageal bronchus (1) Fig. 17: A case of esophageal bronchus (2) Page 19 of 24

20 Fig. 18: A case of tracheobronchial remanant of the esophagus Fig. 19: A case of pulmonary sequestration- intralobar Page 20 of 24

21 Fig. 20: A case of pulmonary sequestration -extralobar (1) Fig. 21: A case of pulmonary sequestration -extralobar (2) Page 21 of 24

22 Fig. 22: A case of congenital pulmonary airway malformation type III Page 22 of 24

23 Fig. 23: A case of congenital pulmonary airway malformation type I Page 23 of 24

24 Conclusion Congenital bronchopulmonary foregut malformation (BPFM) is anamalies derived from defective budding, differentiation and separation from the primitive foregut. BPFM can be classified into foregut anomalies (bronchogenic cyst, esophageal/neuroenteric cyst, tracheoesophageal fistula/diverticula/ stenosis), vascular anomalies (pulmonary sling, alveolar capillary dysplasia, pulmonay isomerism), airway anomalies (tracheal atresia, bronchial atresia, tracheal bronchus, parenchymal anomalies (pulmonary agenesis/ hypoplasia, CLE, CPAM). Understanding the embryological etiology of BPFM and imaging findings will help radiologists to make a rapid and accurate diagnosis. References 1. Biyyam et al. Congenital Lung Abnormalities: Embryologic Features, Prenatal Diagnosis, and Postnatal Radiologic-Pathologic Correlation. Radiographics 2010; 30: Berrocal et al. Congenital Anomalies of the Upper Gastrointestinal Tract. Radiographics 1999;19: Newman et al. Congenital bronchopulmonary foregut malformations: concepts and controversiespediatr Radiol 2006;36: Barnes et al. Bronchopulmonary foregut malformations: embryology, radiology and quandary. Eur Radiol 2003;13: Hur et al. Imaging features of gastrointestinal tract duplication in infants and children: from oesophagus to rectum. Pediatr Radiol 2007; 37: Verma et al. Esophageal Bronchus: Case Report and Review of the Literature. Acta Radiol 2008;49: Sugandhi et al. Esophageal lung: presentation, management, and review of literature. Journal of Pediatric Surgery 2011;46: Geisler et al.tracheal agenesis - a report of two cases Radiology Case Jul; 3(7): Deiraniya et al. Congenital oesophageal stenosis due to tracheobronchial remnants. Thorax 1974;29: Personal Information Page 24 of 24