History
A 7-day-old Red Angus bull calf with a history of respiratory distress of 3 days’ duration was evaluated. This calf had been unthrifty since birth. At the onset of respiratory distress, the owner administered ceftiofur crystalline-free acida (6.6 mg/kg [3 mg/lb], SC, once), with no obvious improvement. On physical examination, the calf was dull but alert and responsive. The calf was tachypneic (100 breaths/min [reference range, 30 to 60 breaths/min]) and cyanotic. Mild dehydration and scleral injection were present. On auscultation of the thorax, lung sounds were increased on the left side and markedly decreased to absent on the right. At this time, supplemental oxygen was provided, with a subsequent mild reduction in respiratory rate. A CBC revealed a stress leukogram (18,614 neutrophils/μL [reference range, 600 to 4,000 neutrophils/μL], 1,589 lymphocytes/μL [reference range, 2,500 to 7,500 lymphocytes/μL], and 2,497 monocytes/μL [reference range, 0 to 200 monocytes/μL]) and a mildly high Hct (47%; reference range, 25% to 45%). Serum biochemical analysis results were largely unremarkable, with the exception of a moderately low total protein concentration (5 g/dL; reference range, 7 to 8.9 g/dL) and a mildly low globulin concentration (2.2 g/dL; reference range, 2.5 to 4.4 g/dL). Three-view thoracic radiography was performed (Figure 1).
Right lateral (A), left lateral (B), and dorsoventral radiographic (C) views of the thorax of a 7-day-old Red Angus bull calf with a 3-day history of dyspnea.
Citation: Journal of the American Veterinary Medical Association 247, 9; 10.2460/javma.247.9.1007
Radiographic Findings and Interpretation
A large, rounded, sharply delineated, thin-walled intrapulmonary structure occupies the right middle and caudal lung lobes and extends across the midline into the left caudomedial aspect of the thorax (Figure 2). The structure is made up of mixed fluid and gas opacities but is largely radiolucent in the right middle aspect of the thorax. The mediastinum and cardiac silhouette are deviated cranially and to the left. A mixed alveolar to interstitial pattern is present in the left cranial and caudal lung fields, suggesting nonobstructive compressive atelectasis. The thorax appears overdistended with elevation of the ribs and caudal displacement of the diaphragm. Differential diagnoses include congenital lobar emphysema, pulmonary and bronchogenic cysts, pulmonary blebs, and emphysematous bullae.
Same radiographic images as in Figure 1. Multiple rounded, multilobulated, mixed fluid and gas opacity intrapulmonary structures are seen overlying the cardiac silhouette and spread throughout the middle and caudal lung fields on the right and left lateral views (short and long arrows). Overdistension of the thorax with elevation of the ribs and caudal displacement of the diaphragm are also seen on the left lateral and dorsoventral views (bracket). On the dorsoventral view, a large, round, radiolucent intrapulmonary structure surrounded by multiple small, thin-walled, multilobulated structures is clearly seen in the right middle and caudal lung fields extending across midline into the left caudomedial aspect of the thorax (straight arrows). The cardiac silhouette and mediastinum are deviated cranially and to the left (curved arrow), and the mixed alveolar to interstitial pattern within the left cranial and caudal lung fields is highly suggestive of nonobstructive compressive atelectasis.
Citation: Journal of the American Veterinary Medical Association 247, 9; 10.2460/javma.247.9.1007
Treatment and Outcome
Left-sided thoracocentesis yielded 20 mL of serous modified transudate. Euthanasia was elected, and the calf was submitted for necropsy. Gross examination revealed marked inflation of the right caudal lung lobe into a large (32 × 23 × 15-cm) gas-filled balloon-like structure that occupied > 75% of the thoracic cavity and displaced the diaphragm caudally. All other lung lobes were severely atelectatic. Histologic examination of the right caudal lung lobe showed that distended sections of the lung lobe were lined by pseudostratified columnar to cuboidal epithelium that resembled bronchiolar epithelium. The epithelial cells were supported by thick fibrous connective tissue, and the structure was separated from adjacent pulmonary lobules by emphysematous interlobular septa. These findings were consistent with a diagnosis of a congenital intrapulmonary bronchogenic cyst.
Comments
Bronchogenic cysts are congenital cystic lesions resulting from the abnormal development of the tracheobronchial tree during the embryonic period.1 Bronchogenic cysts have extremely dilated bronchi or bronchioles that are often distinctly demarcated, with bronchial epithelium within the cyst wall.2 In humans, multiple forms have been described, including both intrathoracic (mediastinum and lung parenchyma) and extrathoracic (neck, retroperitoneal, or subcutaneous) forms.1 Few reports 2–4 of bronchogenic cysts are available in the veterinary literature; however, intrathoracic forms can be associated with dyspnea and decreased respiratory sounds within the affected lung fields.
Diagnostic imaging is an invaluable aid to diagnosing bronchogenic cysts. Radiologically, bronchogenic cysts present as sharply defined, solitary, round to ovoid structures with air, water, or mixed opacities.5 Computed tomography complements radiographic findings; communication with a bronchus in combination with no contrast uptake is characteristic of these congenital anomalies.3–5
Complete surgical excision is the preferred treatment for bronchogenic cysts in human patients and is associated with an excellent prognosis.5 The few reports1–4 that exist in veterinary medicine suggest that this may be the ideal treatment for animal patients as well.
Excede, Zoetis, Florham Park, NJ.
1. Lee JY, Yoon IH, Cho SW, et al. Congenital cervical bronchogenic cyst in a calf. J Vet Diagn Invest 2010; 22: 479–481.
2. Dahl K, Rørvik AM, Lanageland M. Bronchogenic cyst in a German Shepherd Dog. J Small Anim Pract 2002; 43: 456–458.
3. Berchtold B, Meylan M, Gendron K, et al. Successful treatment of an intrathoracic bronchogenic cyst in a Holstein-Friesian calf. Acta Vet Scand 2013; 55: 14.
4. Gadbois J, Blond L, Lapointe C, et al. Computed tomographic evaluation of a bronchogenic cyst in a German Shepherd Dog. Can Vet J 2012; 53: 86–88.
5. Limaïem F, Ayadi-Kaddour A, Djilani H, et al. Pulmonary and mediastinal bronchogenic cysts: a clinicopathologic study of 33 cases. Lung 2008; 186: 55–61.
