A posterior fossa lipoma extending into the cervical spine and subcutaneous space via a cranium bifidum.

We describe a 10-year-old boy with an intracranial lipoma in the posterior fossa. The patient had a subcutaneous tumor of the posterior neck at birth, which was gradually growing and subsequently accompanied by gait disturbance and ataxia. MR imaging revealed the intracranial lipoma in the posterior fossa extending into the cervical spinal canal and subcutaneous space via a cranium bifidum. A surgical operation was performed, but the lipoma could not be removed completely. He had had prominent obesity that might have caused not only enlargement of the intracranial lipoma but also neurological complications. Although intracranial lipomas are usually benign and asymptomatic, early detection of them is quite critical, and body weight control may help to prevent their progression.