T1 sagittal pre gad T1 axial post gad T2 axial

Diagnosis: Pineal epidermoid.

Epidermoid cysts are congenital lesions which arise from the inclusion of ectodermal elements in the neural tube during it's closure in utero. They represent 1% of primary brain neoplasms. Most are located in the cerebellopontine angle as well as the parasellar region. Epidermoid cysts tend to engulf cranial nerves and vessels they come in contact with. They typically present in middle age and have no sex predilection. Calcification is present in up to 1/4 of epidermoid cysts. Enhancement is not seen. On routine MR, they often show signal characteristics identical to CSF which may render them invisible unless there is associated mass effect as in this case. The major differential diagnostic consideration here is a quadrigeminal plate arachnoid cyst. The two may be differentiated from one another via diffusion weighted MR and steady-state free-precession MR imaging. Intrathecal contrast material may also be infused which will infiltrate into the interior of an arachnoid cyst while it will not infiltrate into an epidermoid cyst. This patient's lesion was recurrent. Related Cases













































Cavernous hemangioma Colloid cyst Pineal epidermoid