Two horses with thoracic lymphoma diagnosed using thoracoscopic biopsy

This report describes the use of thoracoscopy in 2 horses to obtain an antemortem diagnosis of thoracic lymphoma. The first horse in this report presented for assessment of weight loss and fever of unknown origin. The second presented with a history of upper respiratory tract noise and coughing during exercise. Although a strong clinical suspicion of neoplasia existed, a definitive antemortem diagnosis of thoracic lymphoma was not made in either case until biopsy samples obtained during standing thoracoscopy were examined.