Introduction: Spontaneous pneumothorax is uncommon in rabbits and could severely affect the respiratory status of the animals. This retrospective case series aimed to provide clinical and diagnostic imaging data associated with this pathological finding in pet rabbits.Materials and Methods: Medical records over the past five years (2017-2022) were reviewed.Results: Four cases were identified: three female and one male rabbit between 5 and 7 years of age. Three rabbits had no history of respiratory signs, and two rabbits presented with respiratory distress. Radiographs revealed severe pneumothorax in two patients. Computed tomography (CT) findings revealed moderate unilateral pneu-mothorax (3/4) and bilateral pneumothorax (1/4). Other concurrent pulmonary findings included emphysema-tous bullae (2/4), cavitary lesions (1/4), and neoplasia (1/4). An infectious component was suspected in all cases and all rabbits were treated with a combination of antibiotics. Several thoracocenteses were performed and chest tubes were inserted in two rabbits. Three rabbits died shortly after the CT scan, whereas the last rabbit recovered temporarily. Histopathology was performed in two cases. The first rabbit had mild-to-severe chronic multifocal granulomatous pneumonia, nephritis, and hepatitis. The second case showed a large epithelioid cell tumor consis-tent with histiocytic sarcoma.Conclusions: Spontaneous pneumothorax is a severe condition that may be life-threatening in pet rabbits. The four cases described provide information about clinical management, evolution over time, and potential etiology.

Spontaneous pneumothorax is uncommon in rabbits and could severely affect the respiratory status of the animals. This retrospective case series aimed to provide clinical and diagnostic imaging data associated with this pathological finding in pet rabbits. Medical records over the past five years (2017–2022) were reviewed. Four cases were identified: three female and one male rabbit between 5 and 7 years of age. Three rabbits had no history of respiratory signs, and two rabbits presented with respiratory distress. Radiographs revealed severe pneumothorax in two patients. Computed tomography (CT) findings revealed moderate unilateral pneumothorax (3/4) and bilateral pneumothorax (1/4). Other concurrent pulmonary findings included emphysematous bullae (2/4), cavitary lesions (1/4), and neoplasia (1/4). An infectious component was suspected in all cases and all rabbits were treated with a combination of antibiotics. Several thoracocenteses were performed and chest tubes were inserted in two rabbits. Three rabbits died shortly after the CT scan, whereas the last rabbit recovered temporarily. Histopathology was performed in two cases. The first rabbit had mild-to-severe chronic multifocal granulomatous pneumonia, nephritis, and hepatitis. The second case showed a large epithelioid cell tumor consistent with histiocytic sarcoma. Spontaneous pneumothorax is a severe condition that may be life-threatening in pet rabbits. The four cases described provide information about clinical management, evolution over time, and potential etiology.