Rapid diffuse pleural thickening due to metastatic meningioma

A 64-year-old man was referred to our hospital because of persistent dyspnoea for the past 1 month. He had recurrent brain anaplastic meningioma after two operations and irradiation. He suffered from right pleural effusion in the previous few months and was diagnosed with malignant mesothelioma via pleural biopsy 1 month prior to coming to our hospital. At his first visit to our hospital, thoracic computed tomography demonstrated rapidly developed large inhomogeneously enhancing pleural thickening up to 3 cm, which surrounded the right hemithorax, together with left-sided pleural effusion. After re-evaluation of the pathological specimens retrieved from the local hospital, he was finally diagnosed with pleural metastasis secondary to anaplastic meningioma (WHO classification, grade 3). Generally, brain meningiomas are believed to be benign and seldom metastasize to other organs. However, the present case clearly demonstrated the unique clinical presentation of anaplastic meningioma, also known as malignant meningioma, which mimicked the pathological and radiological findings of a malignant mesothelioma.