Simultaneous resolution of arachnoid cyst and chronic subdural hematoma after middle meningeal artery embolization: illustrative case

Background: Arachnoid cysts are cerebrospinal fluid-filled spaces that are typically congenital and treated conservatively or with fenestration when symptomatic. Chronic subdural hematomas (cSDHs) can arise in the presence of arachnoid cysts due to fragile leptomeningeal vessels or veins within the cyst wall or cyst lumen, leading to bleeding and subsequent hematoma formation. Middle meningeal artery (MMA) embolization is regularly used for the treatment of cSDH as an alternative to craniotomy and evacuation.

Observations: Here, the authors present the first known report of the simultaneous resolution of an arachnoid cyst and cSDH following MMA embolization in an adult. A 24-year-old male presented to the emergency department with 1 month of worsening headaches. Imaging revealed the presence of a cSDH and ipsilateral arachnoid cyst. The cSDH was treated with MMA embolization using coils exclusively. Follow-up imaging 4 months after embolization demonstrated simultaneous resolution of both the hematoma and the arachnoid cyst.

Lessons: MMA embolization has been used for the treatment of cSDH. In cases in which the hematoma is related to an arachnoid cyst, MMA embolization can also lead to the concurrent resolution of both pathologies. https://thejns.org/doi/10.3171/CASE24192.