Surgical strategy for intracranial endodermal cyst--case report.

Two cases of endodermal cyst of the posterior fossa are reported. A 12-year-old girl presented with severe headache and vomiting caused by increased intracranial pressure. Computed tomography and magnetic resonance (MR) imaging showed a cystic mass occupying the ambient and quadrigeminal cisterns. A 65-year-old woman presented with dizziness, and MR imaging revealed a cystic mass in the posterior fossa. The two patients underwent surgery for decompression and resection of the cyst. Surgical specimens of the cyst walls consisted of a single layer of ciliated columnar epithelium. The diagnoses were endodermal cyst. The optimal surgical goal is total resection of the cyst wall, but the cyst wall sometimes tightly adheres to the adjacent nerves, vessels, and vital structures. The cyst must communicate adequately with the surrounding cerebrospinal fluid space, and a newly closed cyst space must be avoided, by the widest possible resection of the cyst wall.