Sarcomatoid Diffuse Pleural Mesothelioma in an 80-Year-old Woman with Long-Term Response to Nivolumab Plus Ipilimumab: A Case Report

An 80-year-old woman presented to our hospital with the chief complaint of left lateral thoracic pain. Chest computed tomography showed multiple nodular lesions in the left pleura and massive left pleural effusion. Based on clinical findings, imaging, and thoracoscopic pleural biopsy, a diagnosis of sarcomatoid diffuse pleural mesothelioma clinical T2N0M0 Stage IB was made. We administered nivolumab plus ipilimumab as first-line treatment, which resulted in significant reduction of pleural lesions and complete resolution of pleural effusion after two courses. No immune-mediated adverse events except fever were observed. Treatment was discontinued after 16 courses, with no disease recurrence for more than 2 years following the initial treatment. This case suggests that nivolumab plus ipilimumab can be an effective treatment option for older adults with pleural mesothelioma who maintain a good performance status.