 There is an extra-axial fluid collection within the superior cerebellar cistern that measures approximately 16 x 26 mm and follows CSF signal intensity on all pulse sequences. There is resultant mild mass effect upon the tectum and superior cerebellar vermis. There may be some associated mild superior vermian hypoplasia. There is no evidence of intracranial hemorrhage, suspicous mass, or acute infarct. There are no areas of abnormal parenchymal signal. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The major cerebral flow voids are intact. The skull and scalp soft tissues are unremarkable. Bilateral hippocampi are grossly symmetric in size and signal. There is a retention cyst within the left maxillary sinus and minimal fluid within the right mastoid air cells.
1.Superior cerebellar cistern arachnoid cyst with mild mass effect on the superior vermis and tectum. Otherwise unremarkable MRI. 2.No structural abnormalities are seen to suggest seizure focus. If there is continued suspicion, examination per epilepsy protocol can be obtained. 