Fig 5.

49-year-old man with a cystic cervicomedullary schwannoma and hydrocephalus who underwent a third ventriculostomy before excision of the tumor.

A, Axial T1-weighted image through the posterior fossa shows the cystic tumor (arrow) in the left cerebellomedullary angle, compressing the fourth ventricle.

B, Sagittal T1-weighted image shows the cervicomedullary cystic tumor (arrow) with the solid portion inferiorly.

C, Axial MR ventriculogram after third ventriculostomy. The contrast material was injected into the right lateral ventricle. Note contrast material in the right temporal horn, in the suprasellar cisterns (thick arrow), and left sylvian cistern (thin arrow).

D, Axial nonenhanced T1-weighted image for comparison with C.

E, Coronal MR ventriculogram after third ventriculostomy shows contrast material in the bodies of both lateral ventricles. Note contrast material in the left sylvian cistern (arrow).

F, Sagittal MR ventriculogram after third ventriculostomy shows contrast material in the lateral, third, and fourth ventricles. Contrast of lesser intensity is seen in the suprasellar cistern (upper arrow). Note obstruction to the flow of contrast material in the fourth ventricle by the cystic tumor (lower arrow).

G, Sagittal nonenhanced T1-weighted MR image for comparison with F.