Female, 20 years old, with prominent soft tissue along the bilateral ventricular atria on a prior CT examination, presenting with nausea and vomiting. Several anatomic anomalies are identified to account for the findings on prior CT. To begin, it appears that there may be some deficiency of the tentorium which allows a portion of the bilateral cingulate gyrus and the precuneus to prolapse into what would be the posterior fossa. This otherwise normal-appearing parenchyma flattens the superior aspect of the cerebellum to some degree. Also noted is the presence of a prominent posterior superior vermian vein which contributes to the anomalous appearance in this region.No mass or parenchymal edema is identified. No evidence of pathologic parenchymal or extra-axial enhancement is seen. There is no evidence of intracranial hemorrhage or any abnormal extra-axial fluid collection. The ventricular system is within normal limits for size.
The unusual appearance of the posterior fossa on prior CT is accounted for by several congenital anomalies. These include presence of a prominent posterior superior vermian vein, and apparent deficiency of the tentorium which allows downward prolapse of parts of the bilateral cingulate gyrus and precuneus. It is considered very unlikely that these findings would be symptomatic or otherwise related to the patient's presenting complaints.No other significant or acute intracranial abnormalities are identified.