Pulmonary thrombosis with spontaneous pneumothorax

A 12-year-old, neutered male Rough Collie was referred because of a 5-day history of lethargy and respiratory distress. A pneumothorax was detected on a right lateral radiography at the referring veterinary surgeon. Contrast-enhanced CT of the thorax was performed and a severe bilateral pneumothorax with a collapse of the left cranial lung lobe was observed. The underlying cause of the pneumothorax could not be found at that point and an exploratory thoracotomy was performed. The left cranial lung lobe had several perforations and a lobectomy was achieved. A thrombus obliterating a medium calibre artery and associated severe surrounding pulmonary necrosis were detected histologically.