Malignant Meningioma Mimicking Chronic Subdural Hematoma.

Background: Chronic subdural hematoma (CSDH) is the most common disease encountered in neurosurgery. Diagnoses of CSDH are usually made on the basis of computed tomography (CT) images. In this report, we discuss the case of a patient with meningioma whose findings instead suggested CSDH.

Case Description: A 91-year-old woman complained of dizziness. Brain CT imaging revealed a low-density subdural space, following which we diagnosed her with CSDH. On the same day, we performed burr hole surgery. However, when opening the burr hole and cutting the dura, a light yellowish tumor was observed under the dura. After the operation, her condition deteriorated and she died 2 days later. After 10 days, pathologic examination of the tumor specimen led to a diagnosis of atypical meningioma.

Conclusions: In almost all cases, CSDH can be diagnosed using CT images only. However, our patient's true diagnosis was meningioma, rather than CSDH. We rouse attention not to take it for CSDH with a CT image easily.