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Figure 1—Left lateral (A), right lateral (B), and ventrodorsal (C) radiographic views of the thorax of a 12 year-old 7.4-kg (16-lb) neutered male Boston Terrier that was examined because of severe dry cough of 1 week’s duration.

History A 12-year-old 7.4-kg (16-lb) neutered male Boston Terrier was referred because of a progressive severe dry cough of 1 week’s duration. The dog was initially treated with doxycycline and meloxicam, which initially improved the cough.The respiratory signs, however, worsened after 2 days of treatment, as the cough became substantially worse. In addition, the dog started to salivate and became increasingly anorexic. At the time of hospital admission, the dog was moderately dehydrated. A systolic heart murmur (grade II/VI) over the left cardiac apex was detected. Auscultation of the thorax revealed normal lung sounds. Initial findings on CBC and serum biochemical analysis were within reference ranges.Three-view thoracic radiography was performed (Figure 1). Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page → This report was submitted by Alexandre B. Le Roux, DVM, MS, and Daniel Cahn, DVM; from the Units of Diagnostic Imaging (Le Roux) and Small Animal Internal Medicine (Cahn), The Animal Medical Center, 510 E 62nd St, New York, NY 10065. Address correspondence to Dr. Le Roux ([email protected]).

JAVMA • Vol 248 • No. 8 • April 15, 2016

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Figure 2—Same radiographic images as in Figure 1. An ill-defined soft tissue opacity consistent with an alveolar pattern is observed within the accessory lung lobe (long arrows), with associated faint air bronchograms.A linear smoothly marginated soft tissue opacity is visible on both lateral views superimposed on the caudal aspect of the thoracic tracheal lumen, and is approximately 4 cm in length (arrowheads); an ill-defined round gas opacity, surrounded by an irregular thick incomplete soft tissue wall, is also observed on the left lateral view, caudal to the carina and superimposed with the seventh intercostal space (short arrows).

Diagnostic Imaging Findings and Interpretation On thoracic radiographs, an ill-defined soft tissue opacity consistent with an alveolar pattern is observed within the accessory lung lobe (Figure 2).The soft tissue opacity effaces the caudal portion of the cardiac margin and the cranial aspect of the diaphragmatic margin, as well as the thoracic portion of the caudal vena cava.Faint air bronchograms are evident. On the right lateral view, the thoracic portion of the trachea is small in diameter, but appears normal in diameter on the left lateral view.A linear smoothly marginated soft tissue opacity is visible on both lateral views.The linear soft tissue opacity is approximately 4 cm in length and is superimposed with the lumen of the caudal aspect of the thoracic trachea. An ill-defined round gas opacity, surrounded by an irregular thick incomplete soft tissue opacity, is also evident on the left lateral view at the dorsal aspect of the affected accessory lung lobe, caudal to the carina and superimposed with the seventh intercostal space (Figure 2). Radiographic findings are suggestive of a tracheal foreign body (possibly a wood stick) with secondary pneumonia in the accessory lung lobe.The gas opacity dorsal to the acces880

sory lung lobe appears to originate either from the lungs,representing a pulmonary abscess or an infected pulmonary bulla, or from the caudal mediastinum, with consideration given to mediastinitis and possible mediastinal abscess formation. On thoracic CT, a 15-cm-long, soft tissue–attenuating (approx 50 to 60 Hounsfield units), structured, linear foreign body was identified that spanned the stomach, diaphragm, and caudal mediastinum, with the cranial extent of the linear foreign body located in the middle portion of the thoracic trachea (Figure 3). The linear foreign body perforated the thoracic trachea at the level of the carina,between the caudal mainstem bronchi,and could be traced within the caudal mediastinum, through the middle aspect of the diaphragm and cranial portion of the abdomen,where it perforated the stomach wall at the level of the lesser curvature;the esophageal lumen was not penetrated.A caudal mediastinal cavitary lesion was associated with the foreign body. The lesion, identified between the accessory lung lobe and the esophagus, was approximately 2.4 cm in diameter, with an irregular, thick contrast-enhancing rim that surrounded intralesional gas and non–contrast-enhancing fluid. The accessory lung lobe margins and bronchus were moderately to severely attenuated and displaced ventrally by the mediastinal lesion. The dorsal aspect of the accessory lung lobe had a consolidated increased soft tissue attenuation, whereas the remainder of the accessory lung lobe had mild, diffuse soft tissue attenuation.The final diagnosis was a perforating linear foreign body (indicative of a wood skewer), extending from the thoracic trachea to the stomach through the diaphragm, with an associated abscess in the caudal mediastinum and secondary pneumonia or atelectasis of the accessory lung lobe.

Treatment and Outcome A gastrotomy was performed to remove the suspected wood skewer as well as a median sternotomy. The accessory lung lobe was adhered to the diaphragm and slightly discolored, and the caudal mediastinal abscess was observed dor-


sal to the thoracic portion of the caudal vena cava. However, because the abscess was in close proximity to pulmonary vessels, it could not be safely removed.The respiratory signs improved after surgery, but the dog started to regurgitate. Despite medical management, the regurgitations did not improve.A percutaneous endoscopic gastrostomy feeding tube was placed endoscopically. No causes could be identified for the regurgitations during the endoscopic evaluation of the esophagus. Because of worsening of the regurgitations and the dog’s continuing inappetence, the dog was euthanatized. No gross abnormalities were evident on necropsy to explain the regurgitation. Only mild pneumonia was present in a focal area of the accessory lung lobe. Histologic evaluation of the vagus nerves did not reveal abnormalities that would help explain the esophageal dysfunction.Around the site of esophageal adhesion to the accessory lung lobe, the esophagus contained neutrophilic inflammation, and abscess formation was confirmed at the adhesion site.

Comments Two main origins have been reported for thoracic perforating foreign bodies,which can be either inhaled or ingested.1–5 In the dog of the present report, a severe dry cough was initially present without gastrointestinal signs.Therefore, despite the large size of the foreign body, the foreign body is suspected to have been inhaled rather than ingested.Thoracic radiographic and CT findings suggest that the wood skewer perforated the trachea and migrated through the caudal mediastinum and cranial portion of the abdomen. Findings on endoscopic examination of the esophagus and necropsy did not reveal any evidence of esophageal perforation. The caudal lung lobes are a common site to find inhaled foreign bodies.5 Often, the material inhaled is vegetal foreign material, such as foxtails, but many other types of foreign bodies have been described (eg, tooth, food, stone, and bone), usually resulting from orotracheal aspiration.3–5 When this is suspected,the primary imaging test performed should be thoracic radiography. Suspicion of an inhaled foreign body within the accessory lung lobe on thoracic radiographs should be considered when a soft tissue alveolar pattern is recognized in the caudal and midline aspect of the thorax. Once inhaled, some foreign bodies will have the tendency to migrate, either through the pulmonary parenchyma,causing lobar consolidation,or through the pleura or even the diaphragm, leading to pneumothorax, pyothorax, or possibly retroperitonitis.3–5 In these instances, advanced imaging modalities such as thoracic CT may be indicated prior to interventional techniques (eg, bronchoscopy or fluoroscopy) or for surgical planning.

References Figure 3—Postcontrast dorsal multiplanar reconstruction (A) and transverse (B) CT images obtained at the level of the caudal mediastinum of dog in Figure 1. In a soft tissue window (slice thickness, 1.0 mm; window width,250 Hounsfield units [HU];window level,50 HU),a linear well-defined perforating tracheal foreign body, consistent with a wood stick (arrowheads), is evident.The foreign body extends caudally within the caudal mediastinum and through the diaphragm, to the level of the stomach lumen. A cavitary fluid and gas-attenuating, rim-enhancing, lesion (short arrows) exists within the caudal mediastinum, ventral to the esophagus and surrounding the foreign body, consistent with a caudal mediastinal abscess. Ill-defined soft tissue–attenuating parenchyma and consolidation of the adjacent accessory lung lobe (long arrows) are also noted. Ao = Aorta. CVC = Caudal vena cava. E = Esophagus.

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Hunt GB, Worth A, Marchevsky A. Migration of wooden skewer foreign bodies from the gastrointestinal tract in eight dogs. J Small Anim Pract 2004;45:362–367. Sereda NC,Towl S, Maisenbacher HW III, et al. Intracardiac foreign body in a dog. J Vet Cardiol 2009;11:53–58. Cerquetella M, Laus F, Paggi E, et al. Bronchial vegetal foreign bodies in the dog—localization in 47 cases. J Vet Med Sci 2013;75:959–962. Moon SJ, Lee JH, Jeong SW, et al. Chronic bronchocutaneous fistula caused by toothpick foreign body in a Maltese dog. J Vet Med Sci 2012;74:651–655. Schultz RM, Zwingenberger A. Radiographic, computed tomographic, and ultrasonographic findings with migrating intrathoracic grass awns in dogs and cats. Vet Radiol Ultrasound 2008;49:249–255.


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