21 x 11 x 14 mm lesion within the quadrigeminal cistern to the right of midline, following fat on all sequences. No enhancement. Peripheral susceptibility artefact. Associated mass effect on the midbrain with anterior displacement. The remainder of the brain is normal with no diffusion restriction, signal abnormality or abnormal enhancement. The ventricular size and sulcal pattern is appropriate for the patient's age. The dural venous sinuses appear patent. Left maxillary sinus mucous retention cyst.
Conclusion: Quadrigeminal cistern lipoma.