Neoplastic diseases in cattle are rarely documented in veterinary research. They are typically incidental findings in live animals or detected postmortem during slaughter, with few cases yielding successful therapeutic outcomes for farmers. A 9-year-old Limousine beef cow was admitted to the Ruminant Hospital of the National Veterinary School of Toulouse, France. The cow had shown signs of illness for 10 days, including anorexia, arched posture, rapid heart rate, and increased respiration, along with notably diminished cardiac and pulmonary sounds on the right thoracic side. Diagnostic examinations revealed a thoracic sarcoma accompanied by unilateral empyema. The empyema received targeted treatment, while only supportive care was given for the tumor. Despite persistence of the sarcoma, clinical recovery was substantial, and the cow was returned to her farm. Following the withdrawal period, she remained clinically stable but was slaughtered for financial reasons. This case provides a detailed progression from the onset of clinical manifestations and diagnostic workup to laboratory confirmation and postmortem findings.
