Pneumomediastinum Secondary to a Major Response to Nivolumab in Mesothelioma

Introduction: Malignant pleural mesothelioma (MPM) is a rare entity associated with chronic asbestos exposure. Second-line immunotherapy (IT) treatment is associated with very limited benefit, although in selected patients, durable partial responses have been reported. Material and methods: This case describes the evolution of a patient with MPM undergoing palliative pleurodesis at diagnosis who received second-line Nivolumab monotherapy at the Department of Medical Oncology of the Hospital Universitario Infanta Sofia and follow-up at the Department of Thoracic Surgery of the Hospital Universitario Puerta de Hierro. Results: We describe the case of an 83-year-old patient diagnosed with MPM who, after palliative pleurodesis at diagnosis and 4 cycles of platinum-based chemotherapy, had an excellent response to Nivolumab monotherapy. As a consequence of this good response, he presented a pneumomediastinum and subcutaneous emphysema without pneumothorax when a mediastinal-pleural communication developed. Management was conservative and the patient, six months after discontinuation of treatment, is in response with complete resolution of this complication. Conclusion: This case shows a dramatic response to second-line Nivolumab in advanced MPM with the development of a pneumomediastinum as a resultant complication. This finding has not been previously described in the literature.