Sarcomatoid Malignant Mesothelioma Presenting with Intramedullary Spinal Cord Metastasis: A Case Report and Literature Review

Study Design Case report. Objective Malignant mesothelioma (MM) is an uncommon tumor of the pleural epithelium with a predilection for local spread into adjacent tissues. The sarcomatoid type accounts for ∼10% of MM cases and is associated with poorer survival than the epithelioid, desmoplastic, and biphasic types. MM commonly presents with involvement of the vertebral body or epidural space. However, intradural spinal extension of MM is extremely rare. Only eight cases of intradural spinal extension have been reported. We report this rare case and discuss the clinical manifestations of intradural spinal extension of MM with literature review. Methods This report describes the case of a 62-year-old man with Brown-Séquard syndrome and radiculopathy of the left C5 nerve root detected during treatment for pleural sarcomatoid MM. Magnetic resonance imaging (MRI) showed an intramedullary lesion at the C3 level and a small nodule at the left C5 nerve root with cervical canal stenosis. Results The patient underwent surgery, and intramedullary metastasis of sarcomatoid MM was diagnosed. Subsequently, radiotherapy was administered, resulting in temporary improvement of the patient's condition. Thereafter, his condition gradually deteriorated, and follow-up MRI showed a more extensive residual C3 intramedullary lesion. Thus, a second surgery was performed after chemotherapy, but the patient died 5 months after the initial diagnosis. Conclusion We present this rare case, and emphasize intramedullary spinal cord metastasis of MM as differential diagnosis in primary cord lesion.