Surgery of Medulloblastoma of the Fourth Ventricle

Samochernykh K.A., Kim A.V.

(Polenov Research Neurosurgical Institute)

Male patient K. (6 years old) was delivered to the Department of Children's Neurosurgery on February 24, 2001 in a severe state. On admission main manifestations of a disease were as follows: hydrocephalus-hypertension-dislocation syndrome, a symptom-complex of the cerebellum and stem lesion. The patient was sick during 3 months. A pathologic process was characterized by a progradient course. CT examination revealed a large tumor of the fourth ventricle and triventricular hydrocephalus.

An urgent operation was performed on February 26, 2001. It consisted in trephination of the posterior cranial fossa and tumor removal. The squamous portion of the occipital bone was resected along the median line. The right margin of the inferior vermis was dissected on its borderline with a hemisphere. The tumor grew from the right inferior trigone of the rhomboid fossa fundus and an area, which was more lateral, than the trigones of the vagus and hypoglossal nerves and the right funicular body. Its borderline with the cerebellum was distinct. The tumor was removed along its border with almost unchanged tissue. Control CT and MRI examinations of the brain were indicative of internal hydrocephalus and pneumocephalus. Histologic study showed medulloblastoma.

The demonstration goal:

To discuss an unusual initial growth of medulloblastoma, presence of hydrocephalus after tumor removal, problems of pneumocephalus correction after operations with a sitting position of a patient.