Resolution of a persistent pneumothorax by blood patch pleurodesis in a cat ( <i>Felis catus</i> ) with primary pulmonary lymphoma

Abstract An 18‐year‐old, spayed, female, domestic shorthair cat was presented to our hospital with acute dyspnoea following an episode of vomiting. Thoracic radiography revealed a severe pneumothorax. Despite multiple thoracocenteses, the pneumothorax persisted. Under general anaesthesia, computed tomography revealed multiple pulmonary masses. A thoracostomy tube was placed, and fresh whole autologous blood was infused intrapleurally. No air was subsequently retrieved from the thoracostomy tube. While a definitive diagnosis was elusive, a primary lung tumour with intrapulmonary metastasis was strongly suspected from the imaging examination. The cat received supportive care only, but the pneumothorax did not recur. The cat died 11 months after the initial visit. A postmortem examination revealed that CD20‐positive lymphoma cells had extensively replaced the intrinsic structures of the lungs. This case involves a suspected secondary spontaneous pneumothorax caused by primary pulmonary lymphoma in a cat. Intrapleural infusion of autologous blood appeared to be effective in managing persistent pneumothorax.