1 Answer A. Chest radiograph demonstrates a large left-sided diaphragmatic hernia with herniation of bowel contents into the left hemithorax. The stomach is inferior to the diaphragm. There is rightward mediastinal shift and small right hemithorax and lung. The left lung is not well visualized.

Congenital diaphragmatic hernia (CDH) is a developmental discontinuity of the diaphragm that allows abdominal contents to herniate into the chest. The diaphragmatic defect is usually posterolateral (Bochdalek hernia) but may be anterior retrosternal or peristernal (Morgagni hernia) or rarely central. A majority of diaphragmatic hernias occur on the left. Right-sided diaphragmatic hernias occur in only 10% to 15% of cases. Bilateral herniation is uncommon. With left-sided herniation, the stomach is often involved, whereas the liver is often involved when the hernia is on the right; however, the liver may herniate even with left-sided CDH. Both right- and left-sided hernias involve bowel. A sac may cover the herniated abdominal contents.

Pulmonary changes are most severe on the ipsilateral side but can also occur on the contralateral side. The contralateral side is almost always affected in CDH. Differing degrees of bilateral pulmonary hypoplasia may explain the variation in severity among neonates presenting with respiratory distress and CDH. Prognosis is worse in the setting of an abnormal chromosomal microarray, severe associated anomalies, right-sided defect, liver herniation, and lower fetal lung volume. The most reliable prenatal predictor of postnatal survival is absence of liver herniation.

References: Deprest J, et al. Prenatal management of the fetus with isolated congenital diaphragmatic hernia in the era of the TOTAL trial. Semin Fetal Neonatal Med 2014;19:338-348.

Mullassery D, Ba’ath ME, Jesudason EC, Losty PD. Value of liver herniation in prediction of outcome in fetal congenital diaphragmatic hernia: a systematic review and meta-analysis. Ultrasound Obstet Gynecol 2010;35:609-614.

2 Answer B. CT imaging of the chest demonstrates a small right anterior diaphragmatic hernia with herniated omentum and liver. Morgagni hernias are one of the congenital diaphragmatic hernias (CDH) and are characterized by herniation through the foramen of Morgagni. When compared to Bochdalek hernias, Morgagni hernias are:

Reference: Aghajanzadeh M, et al. Clinical presentation and operative repair of Morgagni hernia. Interact Cardiovasc Thorac Surg 2012;15:608-611.

3 Answer A. There is a focal area of mixed consolidation and cystic change in the left lower lobe. There is an aortic branch that originates left lateral to the celiac artery with a separate ostium and courses cephalad to supply the left lower lobe lesion. The venous blood return of this lesion is to the left atrium through the inferior left pulmonary vein.

Bronchopulmonary sequestration (BPS) is a nonfunctioning mass of lung tissue, with airway and alveolar elements, that lacks normal communication with the tracheobronchial tree and that receives its arterial blood supply from the systemic circulation. The subtypes are classified anatomically, as follows:

Located within a normal lobe and lacks its own visceral pleura. ILS accounts for about 75% of BPS.

Located outside the normal lung and has its own visceral pleura. This lesion can also be located below the diaphragm. ELS accounts for about 25% of BPS and is more likely to be associated with other congenital anomalies.

In a hybrid lesion, BPS (either ILS or ELS) occurs in combination with a congenital pulmonary airway malformation (CPAM). These hybrid lesions have histologic features of CPAM and a blood supply from a systemic artery and have been reported in a substantial proportion of cases of BPS.

This is a rare variant of sequestration in which the sequestered lung tissue is connected to the gastrointestinal tract. This may occur in either ILS or ELS. Occasionally, BPFM is used as a general term to include all foregut malformations.

BPS preferentially affects the lower lobes. Extralobar sequestrations almost always affect the left lower lobe; however, 10% of extralobar sequestrations can be subdiaphragmatic.

Traditionally, treatment has been a surgical resection. Extralobar sequestrations with their separate pleural investments can usually be removed sparing normal lung tissue, although, with an intralobar type, segmental resection or even lobectomy will be necessary.

References: Berrocal T, Madrid C, Novo S, et al. Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology. Radiographics 2004;24(1):e17.

Franco J, Aliaga R, Domingo ML, et al. Diagnosis of pulmonary sequestration by spiral CT angiography. Thorax 1998;53(12):1089-1092.

4a Answer C.

4b Answer C. Fetal MRI demonstrates a large mass with multiple T2 hyperintense cysts within the left upper lobe of the lung. The left lower lung is collapsed. The right lung is small. There is left-to-right mediastinal shift. Neonatal chest radiography demonstrates a large lucent lesion within the left hemithorax with mass effect on the right lung and rightward mediastinal shift.

Congenital pulmonary airway malformation (CPAM), previously known as congenital cystic adenomatoid malformation (CCAM), is a developmental anomaly of the lower respiratory tract. Each type of CPAM has distinct pathologic characteristics:

Type 0 is the rarest form and originates from tracheal or bronchial tissue. The cysts are small, with a maximum diameter of 0.5 cm, and are lined with ciliated pseudostratified epithelium. This is a diffuse malformation that involves the entire lung. Gas exchange is severely impaired, and affected infants die at birth.

Type 1 is the most common form of CPAM. Type 1 lesions are comprised of distinct thin-walled cysts 2 to 10 cm in diameter. This type of CPAM has malignant potential. The clinical presentation of type 1 CPAMs depends primarily on the size of the cysts. Large cysts may be detected on prenatal ultrasound.

Type 2 lesions consist of multiple cysts 0.5 to 2 cm in diameter and solid areas that blend into adjacent normal tissue. Extralobar pulmonary sequestrations may have a similar appearance, but unlike type 2 CPAM, these have a systemic blood supply. Other congenital anomalies are observed in patients with type 2 CPAM. Type 2 CPAMs are not at risk for development of malignancy.

Type 3 CPAMs are often very large and can involve an entire lobe or several lobes. They can be a mixture of cystic and solid tissue or be entirely solid. Affected infants present in utero or at birth, usually with severe respiratory distress or death in the neonatal period. This type of CPAM has not been associated with malignancy.

Type 4 lesion cysts have a maximum diameter of 7 cm and consist of nonciliated, flattened, alveolar lining cells, with no mucus cells or skeletal muscle.

References: Biyyam DR, Chapman T, Ferguson MR, et al. Congenital lung abnormalities: embryologic features, prenatal diagnosis, and postnatal radiologic-pathologic correlation. Radiographics 2010;30(6):1721-1738.

Chen WS, Yeh GP, Tsai HD, et al. Prenatal diagnosis of congenital cystic adenomatoid malformations: evolution and outcome. Taiwan J Obstet Gynecol 2009;48(3):278-281.

Rosado-de-christenson ML, Stocker JT. Congenital cystic adenomatoid malformation. Radiographics 1991;11(5):865-886.

5 Answer C. There is an emphysematous and hyperexpanded right middle lobe, of both the medial and lateral segments. Congenital lobar overinflation (CLO) is a developmental anomaly of the lower respiratory tract that is characterized by hyperinflation of one or more of the pulmonary lobes. Other terms for CLO include congenital lobar emphysema and infantile lobar emphysema. Findings include hyperlucency on the affected lung with ipsilateral atelectasis, widened rib spaces, and diaphragmatic flattening. The mediastinum may be displaced away from the affected side and may herniate into the contralateral hemithorax. Patients typically present with respiratory distress, most commonly in the neonatal period, and usually within the first 6 months of life.

There is a predilection for certain lobes:

Left upper lobe, most common

Right middle lobe

Right upper lobe

Rare in the lower lobes

Even though the left upper lobe is the most commonly affected, the right lung is the most common side to be affected.

References: Berrocal T, Madrid C, Novo S, et al. Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology. Radiographics 2004;24(1):e17.

Stigers KB, Woodring JH, Kanga JF. The clinical and imaging spectrum of findings in patients with congenital lobar emphysema. Pediatr Pulmonol 1992;14(3):160-170.

6 Answer B. Esophagram demonstrates extrinsic compression of the distal thoracic esophagus. CT demonstrates fluid-attenuation structure in the posterior mediastinum, which is intimately in contact with, and deforming, the esophagus.

Foregut duplication cysts or esophageal duplication cysts are congenital anomalies that arise during early embryonic development. They are most frequently found in the proximal small intestine, although they can also be found in the esophagus, stomach, and colon. Approximately 80% of cysts do not communicate with the esophageal lumen; the others generally run parallel to and communicate with the esophageal lumen. They are commonly lined by gastric epithelium. This ectopic gastric mucosa is prone to infection, perforation, and hemorrhage. Patients are generally asymptomatic but may complain of dysphagia because of esophageal compression.

References: Callahan MJ, Taylor GA. CT of the pediatric esophagus. AJR Am J Roentgenol 2003;181(5):1391-1396.

Wiechowska-Kozłowska A, Wunsch E, Majewski M, et al. Esophageal duplication cysts: endosonographic findings in asymptomatic patients. World J Gastroenterol 2012;18(11):1270-1272.

7 Answer B. CT demonstrates a heterogeneous right paraspinal mass. There is involvement of the right neural foramina at the levels of T3-T5. Neurogenic tumors represent more than 60% of posterior mediastinal masses. Neuroblastomas and ganglioneuroblastomas are malignant tumors that occur most commonly in children and originate from the sympathetic ganglia. Schwannomas and neurofibromas are benign lesions that arise from the intercostal nerve sheath.

Ganglioneuromas are benign lesions that arise from the sympathetic ganglia and are most common in young adults. Lesions that arise from paraganglionic cells include pheochromocytomas and paragangliomas. A spinal meningocele is a herniation of the meninges through a vertebral column defect or through a foramina. These are most commonly located posteriorly and in the lumbosacral region. Although rare, an anterior spinal meningocele will appear to be a posterior mediastinal mass on imaging. Thoracic teratomas and lymphomas typically occur in the anterior mediastinum. Foregut duplication cysts are typically located in the middle mediastinum.

References: Durand C, Baudain P, Nugues F, Bessaguet S. Mediastinal and thoracic MRI in children. Pediatr Pulmonol Suppl 1999;18:60.

Nakazono T, White CS, Yamasaki F, Yamaguchi K, Egashira R, Irie H, et al. MRI findings of mediastinal neurogenic tumors. AJR Am J Roentgenol 2011;197(4):W643-W652.

8 Answer B. There is a rounded airspace opacity in the right upper lobe consistent with round pneumonia. The mean age of patients with round pneumonia is 5 years and 90% of patients who present with round pneumonia are younger than twelve. Rounded pneumonia is uncommon after the age of eight because collateral airways tend to be well developed by this age. The infective agent in round pneumonia is bacterial. There is no specific bacterium that causes round pneumonia, but because Streptococcus pneumoniae is the most common cause of chest infection, that it is the leading cause of round pneumonia. Follow-up radiographs are not necessary in asymptomatic children with uncomplicated community-acquired pneumonia (CAP). However, in children with complicated CAP or CAP that required intervention, follow-up radiographs help to ensure resolution.

References: Kim YW, Donnelly LF. Round pneumonia: imaging findings in a large series of children. Pediatr Radiol 2007;37(12):1235-1240.

Wagner AL, Szabunio M, Hazlett KS, et al. Radiologic manifestations of round pneumonia in adults. AJR Am J Roentgenol 1998;170(3):723-726.

9 Answer C. Chest radiography demonstrates asymmetric lucency of the left hemithorax as well as decreased pulmonary vascularity. Additionally, there is hyperinflation of the left lung. Differential considerations include left lung air trapping because of foreign body aspiration or sequela of infection (Swyer-James syndrome). Most foreign bodies are radiolucent. Less than 20% of aspirated foreign bodies are radiopaque. The sensitivity for detecting signs of foreign body aspiration improves over time. On chest radiographs, children have air trapping more often, whereas adults have atelectasis more often. The proportion of patients with foreign body aspiration who have normal findings on chest radiographs varies widely in the literature, and atelectasis or consolidation is often not appreciated for at least 24 hours. If foreign body aspiration is suspected, a normal finding on chest radiographs does not exclude the diagnosis. Expiratory chest radiographs are more sensitive for air trapping than inspiratory chest radiographs. Signs are enhanced lucency and relatively low diaphragm position. If the patient cannot cooperate, lateral decubitus views may demonstrate air trapping in the dependent lung. The gold standard diagnostic and therapeutic intervention is bronchoscopy.

References: Capitanio MA, Kirkpatrick JA. The lateral decubitus film. An aid in determining airtrapping in children. Radiology 1972;103(2):460-462.

Passàli D, Lauriello M, Bellussi L, et al. Foreign body inhalation in children: an update. Acta Otorhinolaryngol Ital 2010;30(1):27-32.

10 Answer C. CT imaging demonstrates cylindrical and varicose bronchiectasis within the medial right lower and middle lobes. The classic finding of chronic pulmonary involvement of cystic fibrosis is the presence of thick-walled bronchiectasis. These begin as cylindrical and progress through varicoid to cystic forms. The intervening lung is often densely fibrotic and retracted.

Although the entire lung is affected, there is a predilection for:

Central (perihilar) distribution

Upper lobes

Apical segment of lower lobes

Other features include hyperinflation, regions of consolidation, lymph node enlargement, and pneumothorax and pulmonary arterial hypertension.

HRCT has become an important exam in the monitoring of CF patients and is used to guide therapy and assess response to treatment. Scans are repeated every 6 to 18 months depending on the institution and clinical course. Mucous plugging is of particular importance as it is thought to precede infective exacerbations, and thus, identification of such plugging may be used to trigger changes in therapy.

References: Helbich TH, Heinz-peer G, Fleischmann D, et al. Evolution of CT findings in patients with cystic fibrosis. AJR Am J Roentgenol 1999;173(1):81-88.

Maffessanti M, Polverosi R, Dalpiaz G, et al. Diffuse lung diseases, clinical features, pathology, HRCT. Milano, Italy: Springer Verlag, 2006.

11 Answer C. In the medial inferior right lower lobe abutting the cardiophrenic angle, there is a large cystic mass with multiple septations. In the inferior left upper lobe, there is a peripheral round cyst. Pleuropulmonary blastomas (PPB) are rare, variably aggressive, childhood primary intrathoracic malignancy. Risk factors suggesting a substantial risk of malignancy include:

Pneumothorax is a prominent feature of type 4 CPAM, occurring in about 40% of cases later diagnosed as PPB.

Reference: Priest JR, Williams GM, Hill DA, Dehner LP, Jaffe A. Pulmonary cysts in early childhood and the risk of malignancy. Pediatr Pulmonol 2009;44:14-30.

12 Answer C. On chest radiography, a soft tissue opacity is located at the right superior mediastinum. The US demonstrates a homogeneous soft tissue mass similar in echogenicity to the liver and spleen. The thymus is a lymphatic organ that plays a vital role in the development and maturation of the immune system during childhood, specifically T cells, which regulate cellular immunity, and B cells, which are instrumental in regulating humoral immunity. The thymus attains its maximum size during the first few months of life and does not grow any larger beyond puberty. As children grow older and their immune systems mature, the thymus undergoes physiologic involution. Ultimately, the thymus becomes replaced by fat, yet it maintains its original configuration.

On frontal chest radiographs in infants and young children, the thymus is strikingly large but difficult to distinguish from the cardiac silhouette. The thymus usually has smooth borders and remains visible on radiographs through the age of 3 years. The thymic wave sign, a scalloped or wavy contour of the organ, is created by the impression of the anterior reflection of the ribs. The thymic sail sign is a triangular, slightly convex right lobe of the thymus with a sharply demarcated base caused by the minor fissure.

On US images, the thymus in infants may have multiple linear or branching echogenic foci. The echogenicity of the thymus can be similar to slightly hypoechoic compared to the liver and spleen.

The thymus is very pliable and does not cause compression or displacement of the adjacent structures. This finding can be a particularly important part of a real-time sonographic examination because cardiac pulsations and respiratory motions affect the shape of the thymus. In contrast, solid tumors or diffuse infiltrative processes are less malleable and more rigid.

References: Nasseri F, Eftekhari F. Clinical and radiologic review of the normal and abnormal thymus: pearls and pitfalls. Radiographics 2010;30:413-428.

Nishino M, Ashiku SK, Kocher ON, et al. The thymus: a comprehensive review. Radiographics 2006;26(2):335-348.

13 Answer B. There is a complex heterogeneous enhancing mass centered within the anterior mediastinum. The classic differential for anterior mediastinal masses includes the 4 Ts: “terrible” lymphoma, teratoma, thymoma, and thyroid carcinoma. Lymphoma is the most common anterior mediastinal mass in children. Although Hodgkin lymphoma typically occurs before age 10 years, non-Hodgkin lymphoma is common in both the first and second decades of life. Teratoma accounts for approximately 60% of all germ-cell tumors in the mediastinum. Most are asymptomatic; however, when large, affected patients may present with respiratory distress because of airway compromise. The presence of fat, fluid, and calcified components within an anterior mediastinal mass in a pediatric patient can help differentiate a teratoma from other types of mediastinal masses. Thymomas may be discovered incidentally, although about one-third of patients have symptoms related to local compression or invasion. About 40% of patients with thymomas present with a paraneoplastic syndrome, such as hypogammaglobulinemia, red cell aplasia, or, most commonly, myasthenia gravis. Middle mediastinal masses include vascular lesions, foregut duplication cysts (e.g., bronchogenic cyst), and lymphadenopathy. Posterior mediastinal masses include sympathetic ganglion tumors (e.g., neuroblastoma) and nerve sheath tumors (e.g., schwannoma).

Reference: Ranganath SH, Lee EY, Restrepo R, Eisenberg RL. Mediastinal masses in children. AJR Am J Roentgenol 2012;198:W197-W216. doi: 10.2214/AJR.11.7027. http://www.ajronline.org/doi/abs/10.2214/AJR.11.7027

14 Answer C. There is a large mass in the left hemithorax, which appears to arise from the left sixth rib. There is associated bony destruction. The mass is multiloculated and has an enhancing rim and septations. There is significant shift of the mediastinum, which is almost entirely within the right hemithorax. There is no invasion of the mass into the spinal canal or neural foramina. Ewing sarcomas of the chest wall are malignant tumors affecting children and young adults, originating from either the osseous structures or the soft tissues of the chest wall. On imaging, they are usually characterized as a large extrapulmonary invasive soft tissue masses that are heterogeneous due the presence of hemorrhage, necrosis, or cystic changes. Differential diagnoses of chest wall masses include rhabdomyosarcoma, osteosarcoma, chest wall and pleural metastatic disease, lymphoma, and solitary fibrous tumors of the pleura.

References: Saenz NC, Hass DJ, Meyers P, et al. Pediatric chest wall Ewing’s sarcoma. J Pediatr Surg 2000;35(4):550-555.

Tateishi U, Gladish GW, Kusumoto M, et al. Chest wall tumors: radiologic findings and pathologic correlation: part 2. Malignant tumors. Radiographics 2003;23(6):1491-1508.

15 Answer C. There is a low-density mass located to the left of the aortic arch. The hypodense masses most likely hilar lymph nodes are visualized at the level of the left hilum. In primary pulmonary tuberculosis, the initial focus of infection can be located anywhere within the lung and may present with patchy areas of consolidation or lobar consolidation. Radiographic evidence of parenchymal infection is seen in 70% of children and 90% of adults. Cavitation is uncommon in primary TB. In most cases, the infection becomes localized and a caseating granuloma forms (tuberculoma), which usually eventually calcifies and is then known as a Ghon lesion. Infected children can present with ipsilateral hilar and contiguous mediastinal (paratracheal) lymphadenopathy, usually right sided. These nodes typically have low-density centers with rim enhancement on CT. Occasionally, these nodes may be large enough to compress adjacent airways resulting in distal atelectasis.

References: Jeong YJ, Lee KS. Pulmonary tuberculosis: up-to-date imaging and management. AJR Am J Roentgenol 2008;191(3):834-844.

Leung AN. Pulmonary tuberculosis: the essentials. Radiology 1999;210(2):307-322.

16 Answer D. The scout image from the CT examination demonstrates a soft tissue density in the left abdomen displacing bowel loops superiorly and to the right. There are pulmonary nodules in all lobes bilaterally. Wilms tumors are the most common pediatric renal mass, accounting for over 85% of cases and accounts for 6% of all childhood cancers. It typically occurs in early childhood with peak incidence between 3 and 4 years of age. Approximately 80% of these tumors are found before the age of 5 years. When part of a syndrome, they occur even earlier, typically before 24 months of age. Metastases are most commonly to the lung, the liver, and local lymph nodes. Similar to renal cell carcinoma, tumor thrombus into the renal vein, IVC, and right atrium is also characteristic of advanced disease.