A Rare Case of Schwannoma Arising from the Dura Mater of the Petrosal Surface in the Posterior Cranial Fossa.

BACKGROUND: An intracranial schwannoma originating in the dura mater is extremely rare. Herein, we report a case of schwannoma arising from the dura mater of the petrosal surface in the posterior cranial fossa. CASE DESCRIPTION: A 48-year-old man presented with slight gait disturbance and papilledema. Magnetic resonance imaging showed a T1- and T2-weighted mixed-intensity extra-axial tumor, approximately 4 cm in the maximum diameter with multiple small cysts, in the left posterior cranial fossa. The tumor was heterogeneously enhanced with gadolinium. Operative findings via a lateral suboccipital approach revealed that the tumor did not adhere to any cranial nerves but to the dura mater of the petrosal surface. The tumor was completely excised without any neurologic deficits, and the histologic diagnosis was schwannoma. CONCLUSIONS: The operative and postoperative findings suggested that the schwannoma originated in the meningeal branch of the lower cranial nerves or upper cervical nerves in the dura mater of the petrosal surface in the posterior cranial fossa.

Far-anterior Interhemispheric Transcallosal Approach for a Central Neurocytoma in the Lateral Ventricle.

To describe the far-anterior interhemispheric transcallosal approach for the treatment of a central neurocytoma at the roof of the lateral ventricle. In comparison to the view obtained during the usual anterior transcallosal approach, the far-anterior approach allowed for a higher view of the lateral ventricle to be obtained without further injury or retraction of the corpus callous. Two patients with central neurocytoma in the lateral ventricle were treated with the far-anterior interhemispheric transcallosal approach. Gross-total resections were achieved in both the patients without any postoperative neurological impairments by only 2-3 cm incisions of the corpus callosum. With the anterior transcallosal approach, which was usually used for the intraventricular tumors, the surgical view was relatively downward into the lateral ventricle and suitable for the resection of the tumors located at the base of the lateral ventricle or even in the third ventricle through the foramen of Monro. However, it was relatively difficult to reach the roof of the lateral ventricle using this approach. In contrast, the surgical corridor of the far-anterior transcallosal approach reaches upward to the roof of the lateral ventricle. The far-anterior transcallosal approach provides an alternative to reach the lesions, especially those located in the upper region of the lateral ventricle near important structures, such as the pyramidal tracts.