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1. Bronchoscopy with endobronchial ultrasound
Given the lack of pleural abnormality, pleuroscopy would not be of benefit for this patient. Endoscopic ultrasound would be a useful procedure for evaluating the abnormal mediastinal soft tissue in this patient, but bronchoscopy with endobronchial ultrasound could not only address the mediastinal soft tissue but also sample the abnormal right peribronchial tissue, and transbronchial biopsy could be used to sample the infiltrative abnormality affecting the right lung interstitium, and therefore is the more useful procedure for this patient. Video-assisted thoracoscopic lung biopsy could also provide tissue for diagnosis, but is more invasive than bronchoscopy with endobronchial ultrasound and should be reserved if the latter procedure fails to provide a diagnosis. Catheter pulmonary angiography is most commonly employed as part of right heart catheterization for pulmonary hypertension evaluation or for the diagnosis and treatment of thromboembolic disease, but these disorders are not relevant to this patient.
The patient underwent bronchoscopy with endobronchial ultrasound-directed biopsy of the subcarinal soft tissue as well as transbronchial biopsy of the lung parenchyma- these tissue samples showed no specific abnormalities. The patient then subsequently underwent video-assisted thoracoscopic lung biopsy, which showed no evidence of malignancy or inflammatory change, either acute or chronic. Rather, regions of dilated anastomosing lymphatic channels associated with bundles of smooth muscle- more than simply lymphangiectasis- were noted and were felt to be consistent with a long-standing abnormality. No organisms were identified and no fibrosis was present. With this histopathological interpretation, the imaging findings were re-reviewed and it was noted that no pulmonary veins could be identified on the affected right side, and that this finding was likely developmental in nature. The abnormal peribronchial and mediastinal soft tissue has been described in congenital pulmonary venous atresia, and the hypoplastic right pulmonary artery and volume loss affecting the right thorax, in the absence of active airway obstruction, are more consistent with a developmental disorder than fibrosing mediastinitis. Finally, the complete lack of tracer utilization within the peribronchial and mediastinal soft tissue argues against both fibrosing mediastinitis and malignancy.
Diagnosis: Congenital unilateral pulmonary venous atresia
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