Posterior Fossa Syndrome

Radiology Report

Day #1

Plain CT scan shows a solid, cystic cerebellar heterogeneous mass with compression & effacement of the 4th ventricle; mild obstructive hydrocephalus of lateral & 3rd ventricles. Tumor probably represents polycystic astrocytoma with no evidence of intracranial hemorrhage or infarct.

Day #2

MRI shows cystic abnormality with heterogeneous enhancement from left cerebellar hemisphere, extending superiorly towards midline, compressing the 4th ventricle, and causing mild dilation of the lateral & 3rd ventricles.

Day #4

MRI of the brain and entire spine with and without contrast was performed. Patient has undergone posterior fossa craniotomy for removal of large, central posterior fossa medulloblastoma. At least 2 small nodules in the left superior vermis are present, just inferior to the tentorial edge representing possible local metastasis of small satellite lesions.

No mass effect on basal cisterns, ventricles are midline, and smaller in size than in preoperative MRI. No subdural fluid collection or hemorrhage present.

Cervical: no mass or cord compression
Thoracic: no compression, discrete 4 mm nodule in cauda equina at T12-L1 level
Lumbar: 2 small metastases to the right of midline at L5 and S1, approximately 4 mm traveling along nerve roots

Day #11

Plain CT brain scan shows minimal inward displacement at bone flap with small superficial collection of fluid posterior to the cerebellum present. Edema located within left cerebellar hemisphere, which is unchanged from a prior study. Hemorrhage in 3rd & 4th ventricles has resolved.

Ventriculostomy shunt catheter near foramen of Monroe visible. Ventricles are minimally dilated and unchanged from prior study. There is no evidence of hydrocephalus. Previous intracranial air is resolved with a small amount of hemorrhage along the posterior interhemispheric fissure, but is decreased compared to prior study. No shift of midline structures, intracranial hemorrhage, or acute infarct shown.

Month #3

MRI brain scan with and without contrast shows no abnormal enhancement in tumor bed and no identification of residual tumor. 2 small nodules in the left superior vermis that were very difficult to see on initial postoperative study are not visible on current scan.

Ventricles have not changed in size compared to initial postoperative study. No abnormalities over cerebral hemispheres and no infarct visible.

Month #6

MRI brain scan with and without contrast showed no significant change compared to previous MRI. Mild encephalomalacia present in the medial aspect of the left cerebellar hemisphere. No evidence of mass lesion or abnormal nodules in post-surgical tumor bed or elsewhere. Ventricular system stable with no signs of hydrocephalus.

Complete opacification seen in the left maxillary sinus, partial ethmoid sinuses bilaterally, mild to moderate mucosal thickening in sphenoid sinuses and right maxillary sinus, mild mucosal thickening of frontal sinuses — sinusitis slightly worse than previous exam.