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Congenital Lung Abnormalities in Neonates and Adults represent 5%-19% of all congenital anomalies, covering a spectrum from devastating neonatal disorders to incidental findings in adulthood. |
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This chest radiograph was obtained on a newborn infant with respiratory distress after delivery. Which of the following conditions is a possible cause of her congenital lung disorder? A. Oligohydramnios B. Diaphragmatic hernia C. Thoracic cage defects D. All of the above |
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Answer: D. All of the above This CT scan of the same patient shows diaphragmatic herniation with an intrathoracic liver (left arrow); the left lung is normal (right arrow). This infant has pulmonary hypoplasia, which is usually the result of an intrauterine process that limits normal development of the distal pulmonary tissues. Causes include oligohydramnios (from the obstructed, enlarged bladder), diaphragmatic hernias, and thoracic cage defects. Severity depends on the timing of the insult in relation to the stage of lung development. Although severe hypoplasia is incompatible with life, gas exchange may be unimpaired in unilateral hypoplasia if the normal lung receives sufficient air and blood flow. Treatment is supportive. |
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This chest radiograph of a newborn girl with respiratory distress shows dense lungs with the suggestion of a right lung that is more voluminous than the left. Which of the following modalities is typically used to diagnose her condition? A. CT scan B. Bronchiolar lavage C. Lumbar puncture D. Prenatal ultrasound |
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Answer: A. CT scan This patient has a congenital pulmonary airway malformation (CPAM), or congenital cystic adenomatoid malformation, in the right upper lung, best diagnosed by CT. CPAMs, which are often identified prenatally through routine ultrasonography, are areas of adenomatous overgrowth of the terminal bronchioles with a consequent reduction in alveolar growth. Lesions not detected prenatally usually present in the newborn period with respiratory distress. A solid or cystic chest mass on radiography suggests the diagnosis. CPAMs communicate with the bronchial tree, and physiologic alveolar fluid seen initially is eventually resorbed, as shown in this radiograph obtained the following day on the same patient. |
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Overinflation of larger CPAMs and compression of surrounding lung tissue may cause pressure on adjacent structures, leading to polyhydramnios or hydrops fetalis. Smaller CPAMs can persist into childhood and may remain undetected or may cause recurrent infection, intermittent chest pain, or dyspnea. Resection is recommended, even for asymptomatic CPAMs, because of the recognized potential for malignant transformation. Open in utero lobectomy for CPAM associated with fetal hydrops is under investigation, but the benefits have not yet been determined. This CT scan shows one dominant cyst (arrow) with multiple adjacent smaller cysts. |
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This chest radiograph obtained of an infant with respiratory distress, cough, and fever shows a difference in aeration between the 2 lungs. Which of the following is most compatible with his presentation? A. Asthma B. Bronchiolitis C. Congenital lobar emphysema D. Extrapulmonary sequestration |
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Answer: D. Extrapulmonary sequestration Any difference in aeration between the 2 lungs should prompt further investigation. In this case, the patient has a pulmonary sequestration -- a cystic or solid area of lung tissue not connected to the tracheobronchial tree. Patients may present with a chronic cough or with recurrent pneumonia or respiratory problems in the same anatomic location. Sequestrations are classified as intrapulmonary (surrounded by normal lung tissue) or extrapulmonary (with its own pleural lining). Intrapulmonary sequestrations may occur in either lung, often not manifesting until late in childhood or adolescence. Extrapulmonary sequestrations are usually on the left side and may present with feeding difficulties if connected to the gastrointestinal tract. A subdiaphragmatic extrapulmonary sequestration (large opacity below left costophrenic angle) is shown. |
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Sequestrations are composed of nonfunctioning primitive tissue with an anomalous blood supply from the systemic circulation rather than the pulmonary circulation. Multiple feeding vessels are present in 15%-20% of cases.[1] Resection is recommended, and preoperative angiographic identification of the vascular supply is crucial. This angiogram shows a sequestration (upper arrow) with an arterial supply from the infradiaphragmatic aorta (lower arrow). |
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This contrast-enhanced CT angiogram shows a subpulmonic sequestration (punctuate calcifications) with an arterial supply from the celiac axis (white arrows) and venous drainage via the left renal vein (red arrow). Whereas only 10% of intrapulmonary sequestrations are associated with other congenital anomalies,[2] more than 50% of extrapulmonary sequestrations are associated with anomalies such as congenital diaphragmatic hernias, CPAM, and congenital heart disease.[3] |
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This chest radiograph of a newborn infant with severe respiratory distress shows marked lucency and hyperexpansion in the left hemithorax. Which of the following is the likeliest diagnosis? A. Tension pneumothorax B. Congenital cystic adenomatous malformation C. Congenital lobar emphysema D. Respiratory distress syndrome |
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Answer: C. Congenital lobar emphysema Congenital lobar emphysema (CLE) is the result of massive overinflation in one or more pulmonary lobes from intrinsic (eg, airway cartilage deficiency) or extrinsic (eg, bronchial compression by anomalous pulmonary vasculature) causes. CLE usually presents in the newborn period with cough, wheezing, respiratory distress, and cyanosis. Older children may present with recurrent lung infections. Initial chest radiographs may show a fluid-filled lobe that later changes to a hyperlucent expanded lobe. The presence of lung markings helps distinguish CLE from tension pneumothorax. This histology slide shows markedly distended alveoli. |
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CLE most commonly affects the left upper lobe. Hyperexpansion results in compressive atelectasis of the ispilateral lung lobes as well as mediastinal shift. Treatment usually begins with bronchoscopy to exclude an endobronchial lesion followed by surgical lobectomy. This CT scan shows marked hyperaeration of the left upper lobe with a rightward mediastinal shift. CLE may be associated with polyalveolar lobe, a generally benign anomaly in which the number of alveoli is increased to more than 3 times normal. |
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This chest radiograph showing a right paratracheal mass (arrow) was obtained on a 21-year-old man with fever, chest pain, and difficulty swallowing. He reports 1 prior episode of pneumonia. What is the likely cause of the congenital lung malformation shown on his chest radiograph? A. Abnormal budding of the tracheal diverticulum B. Maldevelopment of the terminal bronchiole structures C. Pulmonary lymphangiectasis D. Oligohydramnios resulting in poorly developed lung tissue |
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Answer: A. Abnormal budding of the tracheal diverticulum This patient has a bronchogenic cyst, a result of abnormal budding of the ventral foregut. Bronchogenic cysts usually do not become clinically apparent unless they are infected or compress other structures, as in this patient with recurrent pneumonia and dysphagia. In infants and small children, these cysts can be life-threatening when they compress vital structures. The best diagnostic clue is a well-defined mediastinal mass, as 85% of bronchogenic cysts are mediastinal. Although more than half of patients are asymptomatic, surgical excision is usually recommended because potential for infection is high. This CT scan shows a large cyst in the right upper lobe. |
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A 62-year-old woman complains of dyspnea and exercise intolerance. You note the skin findings shown. Which congenital lung malformation is most likely to explain her respiratory symptoms? A. Congenital lobar emphysema B. Pulmonary arteriovenous malformation C. Extrapulmonary sequestration D. Polyalveolar lobe |
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Answer: B. Pulmonary arteriovenous malformation Pulmonary arteriovenous malformations (PAVMs), or pulmonary arteriovenous fistulae, are abnormal communications between the pulmonary arterial and venous systems without interposed capillaries. Symptoms are unusual in childhood. However, by adulthood, 50% of patients have at least exertional dyspnea. Patients with cutaneous telangiectasis, such as this patient, are likely to have hereditary hemorrhagic telangiectasia (HHT or Rendu-Osler-Weber disease); hemoptysis is most common in such patients. A continuous bruit is often heard over the lesion. PAVMs are usually seen as well-defined opacities on chest radiography, as with the left lower lobe PAVM shown (arrow). |
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PAVMs are multiple in as many as 50% of patients and bilateral in 10%. Most are subpleural and are found more frequently in the lower lobes. Complications include bleeding, infection, and embolus. Patients with HHT are likely to have multiple PAVMs and progressive symptoms. Findings on CT with contrast are usually diagnostic, as in this study of a large left lower lobe PAVM showing a feeding vessel to the left atrium. Hypoxemia on an exercise study may be an indication for therapy; a lung scan or bubble echocardiogram may help detect a right-to-left shunt. PAVMs are treated by resection. If this is not possible, lesions can be embolized. PAVM may also be an acquired disorder in patients with chronic liver disease (eg, cirrhosis). |
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This chest radiograph was obtained as part of a pre-employment evaluation for a healthy, asymptomatic 42-year-old man. Which of the following congenital malformations is this patient most likely to have? A. Bronchogenic cyst B. Congenital cystic adenomatous malformation C. Pulmonary hamartoma D. Pulmonary sequestration |
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Answer: C. Pulmonary hamartoma Pulmonary hamartomas often remain undetected, presenting in adulthood as an incidental radiographic finding of an asymptomatic, slow-growing, solitary lung nodule. They are the most common benign lung tumors and the third most common cause of solitary lung nodules. Roughly one third of cases show the classic "popcorn calcifications" seen on the previous slide. CT allows more detailed evaluation of the nodule's typical characteristics, such as a lobulated contour with fat and calcification (shown). Diagnosis is confirmed by biopsy, with resection performed for diagnosis or for symptoms of airway obstruction. |
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A 27-year-old woman presents with a 1-week history of a cough. The radiologist points out an usual finding on her chest radiograph. Image courtesy of Wikimedia Commons. Which of the following is seen on her study? A. Bronchogenic cyst B. Pulmonary hamartoma C. Azygos lobe D. Pulmonary sequestration |
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Answer: C. Azygos lobe An azygos lobe (arrowheads) is a malformation of the right upper lobe caused by an aberrant azygos vein (arrow) suspended by a pleural mesentery. An azygos lobe is a radiographic curiosity without clinical significance that is seen in up to 0.5% of the general population. Image courtesy of Wikimedia Commons. |
