Chronic subdural hematoma of the posterior fossa treated by suboccipital craniotomy.

Background: Chronic subdural hematoma (CSDH) of the posterior fossa is uncommon in adults. Only a few cases have been reported, and most of these were secondary to head injury or anticoagulant therapy. We herein describe a case of successful surgical treatment of CSDH in the posterior fossa after surgical removal of a large supratentorial and infratentorial dermoid cyst.

Case Description: A 71-year-old woman underwent removal of a left supratentorial and infratentorial dermoid cyst via a left transzygomatic approach. Three years, 6 months after surgery, screening computed tomography revealed CSDH in the supratentorial and infratentorial regions. Four months later, the patient was transferred to the emergency department with cerebellar ataxia, vomiting, and deterioration of consciousness. Two hematomas, one in the supratentorial region and one in the infratentorial region, were greatly compressing the brain, and seemed to be separate lesions. It was difficult to judge on computed tomography whether there was communication between these two hematoma cavities. The patient underwent hematoma removal via suboccipital craniotomy for the posterior fossa CSDH to resolve brain stem compression. Burr-hole irrigation was used for the supratentorial CSDH to avoid upper herniation. The patient recovered uneventfully and was discharged with no neurological deficits.

Conclusion: Although the optimal treatment for CSDH of the posterior fossa remains unclear because of the limited number of previous reports, direct decompression of the posterior fossa via suboccipital craniotomy should be considered, especially when CSDH exists primarily at the cerebellopontine angle and strongly compresses the brain stem.