Mediastinitis is a life-threatening condition caused by purulent effusion in the mediastinum. Rapid surgical treatment and proper clinical approach are the cornerstones for healing. This case report highlights an unusual cause of onset for this condition and describes how various approaches for this disease could be complementary. A 39-year-old man was referred to our department, with a history of recurrent pneumonia and upper left lung lobe's opacity, from the intensive care unit (ICU) for the CT finding of mediastinitis. We performed a video-assisted left mini-thoracotomy and subxiphoid access to drain the purulent collection from mediastinum and pleural cavities. Then we started an unprecedented off-label multi-drug antibiotic treatment with ceftolozane/tazobactam plus fosfomycin and, after 15 days, we performed an upper left lobectomy. The histological finding was suggestive of the presence of a lung's teratoma, which had caused the mediastinitis. The patient was dismissed and is, nowadays, in good health. Identifying mediastinitis is essential for his rapid and proper treatment, and the surgical approach is not always sufficiently effective. The present case report underlines that it is mandatory to remember that rapid surgical intervention, with the right timing, right clinical approach, and multidisciplinary approach, are critical factors for mediastinitis treatment.

Mediastinitis is a life-threatening condition caused by purulent effusion in the mediastinum. Rapid surgical treatment and proper clinical approach are the cornerstones for healing. This case report highlights an unusual cause of onset for this condition and describes how various approaches for this disease could be complementary. A 39-year-old man was referred to our department, with a history of recurrent pneumonia and upper left lung lobe's opacity, from the intensive care unit (ICU) for the CT finding of mediastinitis. We performed a video-assisted left mini-thoracotomy and subxiphoid access to drain the purulent collection from mediastinum and pleural cavities. Then we started an unprecedented off-label multi-drug antibiotic treatment with ceftolozane/tazobactam plus fosfomycin and, after 15 days, we performed an upper left lobectomy. The histological finding was suggestive of the presence of a lung's teratoma, which had caused the mediastinitis. The patient was dismissed and is, nowadays, in good health. Identifying mediastinitis is essential for his rapid and proper treatment, and the surgical approach is not always sufficiently effective. The present case report underlines that it is mandatory to remember that rapid surgical intervention, with the right timing, right clinical approach, and multidisciplinary approach, are critical factors for mediastinitis treatment.