Benign neoplasm of brain [225.0], Reason for Study: ^Reason: hx schwannoma s/p radiation History: none The patient did not want to have contrast enhancement. Therefore, only precontrast enhanced MRI scan was performed.Extra-axial mass located on the prepontine cistern as well as lateral aspect of right side cavernous sinus are again seen.Measured maximum diameter of the prepontine cistern lesion is about 31.3 mm and that of a right Meckel's cave and right cavernous sinus lesion is about 26.6 mm. Comparing to prior scan, the size, extent and MR characteristics do not show any significant interval change.Right side lower pons as well as middle cerebellar peduncle again shows high signal intensity on FLAIR imaging, no change since prior scan.Previously seen left basal ganglia lesion does not show interval change in FLAIR signal intensity but demonstrates no abnormal restricted diffusion indicate prior small ischemic infarction.There is no evidence of extension of the mass into the right internal auditory canal. No evidence of acute ischemic or hemorrhagic lesion on this scan.The ventricles, sulci and cisterns are unremarkable. The paranasal sinuses and mastoid air cells are clear.
1. Right prepontine, right Meckel's cave and right cavernous sinus extra axial mass lesions likely represent meningioma is again demonstrated without showing any significant interval change in terms of maximum diameter, and MR characteristics.2. No change of external compression related edema on the pons and right middle cerebellar peduncle since prior scan. 