Remarkable response to nivolumab in sarcomatoid malignant pleural mesothelioma with high PD-L1.

We report herein a case of sarcomatoid malignant pleural mesothelioma (MPM) with high PD-L1 expression who was refractory to standard chemotherapy but had a remarkable and sustained response to nivolumab. A 78-year-old man presented with right chest pain. Computed tomography (CT) showed a solid mass extending to the right pleura. Histopathological examination revealed the proliferation of spindle to pleomorphic ovoid shaped tumour cells, which are positive for calretinin and podoplanin. The patient was diagnosed with sarcomatoid MPM. Despite treatment with carboplatin and pemetrexed, the primary lesion rapidly progressed and new multiple pleural metastases were observed. Although his performance status decreased with advancing of symptoms and adverse events, nivolumab was administered. After the nivolumab treatment, CT showed a significant reduction in pleural tumours with a marked improvement in symptoms. In the primary specimens, TPS of PD-L1 was 80%. The patient has continued this treatment with sustained and remarkable effectiveness with good quality of life (QOL).