Vermian epidermal cyst developing in the fourth ventricle. A case report

A 34-year-old man presented with recent severe headache. Neurological exami nation Sound gait disturbances and a static cerebellar syndrome. The CT sca n showed a tumor located in the fourth ventricle and which presented with a density close to that of the cerebellar parenchyma, without contrast enhan cement, associated with an enlargement of the third and rite lateral ventri cles. MRI showed that the tumor had an heterogeneous hyposignal on TI-weigh ted images and an hypersignal an T2-weighted images, without associated ede ma; the roof of the fourth ventricle was displaced upward and the brain ste m forward At operation, an encapsulated epidermal cyst, developed from the cerebellar vermis, without attachment to the poor of the fourth ventricle, was totally removed. Epidermal cysts of the fourth ventricle are unusual le sions; their capsule often adhere to the floor and cannot be totally remove d. Those developed from the cerebellar vermis seem to be rarer With the rue of MRI, their true origin could be suspected. In these cases, the cysts ca n be totally removed, reducing the risk of recurrence.