Solitary Extramedullary Plasmacytoma Mimicking Acute Subdural Hematoma

Background Solitary extramedullary plasmacytoma (SEP) is a plasma cell neoplasm located outside the bone. It is rarely observed in the intracranial area. It is very difficult to diagnose this condition radiologically before surgery. In addition, dural SEP is usually misdiagnosed. Case Description We report a case of plasmacytoma that presented as altered mental status after head trauma, located in the subdural area. We also describe its differential diagnosis and treatment by total removal and adjuvant radiotherapy. The 66-month follow-up findings showed distant plasmacytoma development, which was treated with radiotherapy alone. Conclusions Some pathological entities should be considered in the differential diagnosis of acute subdural hematomas. Furthermore, to the best of our knowledge, we report the first case of dural SEP mimicking acute subdural hematoma.