Phrenic Nerve Paralysis as the Initial Presentation in Pleural Sarcomatoid Mesothelioma

A 74-year-old man was referred to our hospital because of persistent cough. A chest radiograph revealed an elevation of the right diaphragm. Computed tomography (CT) images revealed a small nodule localized on the right mediastinum. Five months later, the nodule had grown and was diagnosed as malignant pleural mesothelioma (MPM) by a CT-guided needle biopsy. The patient underwent combined chemotherapy, but the disease progressed rapidly and he passed away. On autopsy, microscopic findings and immunohistological examinations supported the diagnosis of sarcomatoid mesothelioma. Therefore, we diagnosed this rare case as localized sarcomatoid MPM showing phrenic nerve paralysis as an initial presentation.