Intracranial multiple myeloma masquerading as subdural hematoma: illustrative cases.

Background: Intracranial involvement in multiple myeloma (MM) is a rare clinical presentation, often mimicking other conditions such as subdural hematoma (SDH) and resulting in poor prognosis.

Observations: This case series highlights 2 older female patients, one with a prior diagnosis of MM, who developed subdural masses resembling SDH. Both cases were associated with significant cerebral edema and mass effect. Biopsies confirmed plasma cell neoplasms, and both patients underwent tailored treatment, including corticosteroids, radiation therapy, and systemic chemotherapy. The patients showed clinical and radiographic improvement posttreatment.

Lessons: These cases underscore the importance of maintaining a broad differential in patients with subdural collections, particularly if associated with significant vasogenic edema or in those with a history of MM. Nonoperative management is effective, despite mass effect. https://thejns.org/doi/10.3171/CASE25347.