Ruptured intracranial dermoid cyst
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There is a 20 x 35 x 50 mm large extra-axial lobulated abnormal signal (high on T1 and T2 images) mass lesion located at the suprasellar cistern with posterior creeping into the right perimesencephalic cisterns, cerebellopontine angle and right Meckel cave.
The mass shows a marked pressure effect on the brainstem and right brachium pontis causing to the left-sided deviation of these structures. The mass is indenting and mildly displacing the right posterior cerebral artery and ipsilateral intracranial nerves originated from the midbrain and pons is noted. The mass shows thin rim enhancement after contrast injection and dropped signal at the fat suppression sequences.
There are also high signal intensity droplets/foci (on T1 images) at the subarachnoid space consistent with rupture.
An intracranial dermoid cyst is an uncommon lesion with characteristic imaging findings. It can be thought of as along the spectrum: from the epidermoid cyst at one end and teratoma at the other. It can be asymptomatic with development of symptoms due to mass effect or rupture.
On imaging, it is usually well-defined lobulated midline mass that has low attenuation on CT and high signal intensity on T1-weighted MR images because of the fat component. Typically they do not enhance after contrast administration.