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Localized persistent pulmonary interstitial emphysema Article in Journal of Pediatric Surgery · July 2006 DOI: 10.1016/j.jpedsurg.2006.01.071 · Source: PubMed
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Journal of Pediatric Surgery (2006) 41, 1191 – 1193
www.elsevier.com/locate/jpedsurg
Pediatric surgical image
Localized persistent pulmonary interstitial emphysema Jagadish Rao, Mitchel I. Hochman, Grant G. Miller* Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 4N3
A 3-week-old premature female infant was referred to our institution with progressively worsening respiratory distress. She was born at 29 weeks’ gestational age with radiologic evidence of mild respiratory distress syndrome. She required only minimal supplemental oxygen until her third week of life, when she developed worsening respiratory distress requiring mechanical ventilation. A new chest radiograph (Fig. 1) demonstrated hyperinflation of the left hemithorax with coarse reticular markings throughout the left lung. Computed tomography (CT; Fig. 2) revealed innumerable cystic spaces of varying sizes occupying the entirety of the left upper lobe, with no appreciable normal lung parenchyma interposed. She failed to wean from mechanical ventilation and underwent an urgent left thoracotomy. The entire upper lobe was grossly involved with cystic lung pathology (Fig. 3). This was treated by an uncomplicated left upper lobectomy, and the patient was weaned from mechanical ventilation over the next 3 days. The histopathology (Fig. 4) demonstrated cyst-like cavities lined by an irregular layer of cells within the lung parenchyma. These cells were mostly mononuclear admixed with foreign body–type multinucleated giant cells. The cysts were interspersed with essentially normal-appearing pulmonary tissue. Occasional air spaces were questionably dilated, particularly at the periphery of the lung beneath the pleural surface. However, widespread emphysematous changes were not apparent; neither was there any significant intraalveolar or interstitial inflammatory cell infiltrate. These findings were diag-
* Corresponding author. Tel.: +1 306 966 8141; fax: +1 306 966 7988. E-mail address:
[email protected] (G.G. Miller). 0022-3468/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2006.01.071
nosed as localized persistent pulmonary interstitial emphysema (PIE). Pulmonary interstitial emphysema is characterized by gas dissecting the interstitial tissues of the lung. It has 3 distinct forms: acute PIE, localized persistent PIE (LPPIE), and diffuse persistent PIE. This may occur as a result of increased intraalveolar pressure secondary to aspiration, partial bronchiole occlusion, or positive pressure ventilation and may cause overdistended pulmonary alveoli with resultant dissection of air into the interstitium. In acute PIE, the air tracks from the interstitium into adjacent spaces, causing pneumothorax, pneumomediastinum, or pneumopericardium. In persistent PIE, the air persists within the interstitium rather than tracking elsewhere. It may be localized to one lobe or diffusely present throughout the lung parenchyma. Acute PIE most often develops with hyaline membrane disease. It is less commonly associated with high ventilatory support provided to infants with obstructive air trapping secondary to meconium aspiration or pulmonary hypoplasia. Localized persistent PIE is also associated with hyaline membrane disease but can, as in this case, develop spontaneously. Diffuse persistent PIE is most commonly associated with bronchopulmonary dysplasia. These 3 forms of PIE can be distinguished radiographically. On chest roentgenograms, LPPIE appears as a unilobar or multilobar multicystic, air-filled mass with mass effect. This may cause the contralateral lung to collapse, often increasing oxygen requirements and causing greater air trapping. Chest CT is helpful in differentiating LPPIE from other lesions, such as congenital cystic adenomatoid malformation or congenital lobar emphysema, as the abnormal air collection is in the interstitium and surrounds the bronchovascular bundles. The bronchovascular bundles
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Fig. 1 Anteroposterior chest radiograph demonstrating hyperinflation of the left hemithorax with coarse reticular markings throughout the left lung.
Fig. 3 Operative photograph demonstrating the multicystic pathology involving the entire left upper lobe.
may sometimes appear as a round or linear soft-tissue component within the cyst lumen or wall. Typically, a congenital cystic adenomatoid malformation is present at birth, and the cysts are more variable in size. Congenital lobar emphysema typically involves one lobe, but its unilocular cystic appearance helps differentiate it from the multilocular cystic appearance of LPPIE. Localized persistent PIE has a characteristic pathologic appearance of multiloculated cysts separated by normal lung parenchyma. These cystic spaces are variable in size, usually measuring up to 3 cm. The cyst walls are irregular, and usually 1 to 2 cell layers in thickness. The lining of the cyst walls is devoid of smooth muscle tissue and instead composed of fibrous connective tissue with a lining of mononuclear cells. Pathognomonic of this entity is the finding of multinucleated foreign body–type giant cells within the cysts walls. It is important to distinguish LPPIE from other cystic lesions because the initial management of LPPIE may be
nonoperative by selective intubation and selective bronchial obstruction or decubitus positioning. Resection of the involved lobe may be indicated when a relatively large discrete cystic area significantly reduces lung volume and produces persistent respiratory distress, produces atelectasis and recurrent infections, or leads to pneumothoraces. In summary, LPPIE should be considered in premature infants with cystic malformation of the lung with or without respiratory distress. It may or may not be associated with hyaline membrane disease. It can usually be distinguished from congenital cystic malformation of the lung by CT and may resolve with conservative therapies. Operative treatment should be considered when the diagnosis is unclear or for progressive respiratory distress, ventilator dependence, or complications such as recurrent pneumonia or recurrent pneumothoraces.
Fig. 2 Computed tomography of the chest revealing multiple cystic spaces of varying sizes occupying the entire left upper lobe.
Fig. 4 Hematoxolin and eosin–stained histopathology demonstrating cyst-like cavities lined by an irregular layer of cells within the lung parenchyma. These cells are mostly mononuclear admixed with foreign body–type multinucleated giant cells. The cysts were interspersed with essentially normal-appearing pulmonary tissue.
Localized persistent pulmonary interstitial emphysema
Further reading Scully RE, Mark EJ, McNeely WF, et al. Case 30-1997: case records of the Massachusetts General Hospital. N Engl J Med 1997;337(13):916 - 24. Stocker JT, Madewell JE. Persistent interstitial emphysema: another complication of the respiratory distress syndrome. Pediatrics 1977;59:847 - 57. Jabra AA, Fishman EK, Shehata BM, et al. Localized persistent pulmonary interstitial emphysema: CT findings with radiographic-pathologic correlation. AJR Am J Roentgenol 1997;169:1381 - 4.
1193 Drut R, Drut M. Pathological case of the month: persistent interstitial pulmonary emphysema presenting as a large unilocular cyst in an asymptomatic infant. Arch Pediatr Adolesc Med 2000;154:87 - 8. Stocker JT, Drake RM, Madewell JE. Cystic and congenital lung disease in the newborn. Perspect Pediatr Pathol 1978;4:93 - 154. Schneider JR, St Cyr JA, Thompson TR, et al. The changing spectrum of cystic pulmonary lesions requiring surgical resection in infants. J Thorac Cardiovasc Surg 1987;89:332 - 9.
