Benign neoplasm of cranial nerves [D33.3], Reason for Study: ^Reason: Eval acoustic neuroma for change: PLEASE ONLY DO WITH CONTRAST. PATIENT DIDN'T COMPLETE PREVIOUS EXAM History: yearly imaging IAC MRI:There is evidence of left retrosigmoid craniectomy with the left inferolateral cerebellar hemispheric encephalomalacia indicating postoperative changes.There are multilobulated enhancing masses on the left cerebellopontine angle adjacent to the left IAC which extends underneath of the left side tentorium. In addition, there are multiple lobulating low signal intensity lesions on both T1 and T2 images intermingled with enhancing mass lesions. There is also not well enhancing nodular lesion (8.8mm x 6.9mm) on the anteromesial aspect of the mass, around the origin of the left 6th nerve (series 3101, image 105/353)Constellation of these findings indicate possible postoperative residual tumor with different compartments showing different MR characteristics and mixed with organized blood products or calcified portions.The enhancing mass is overriding the left middle cerebellar peduncle and extends superoposteriorly following the left side ambient cistern. The measured size of the enhancing mass is about 15.4mm x 9.2mm at the level of left IAC and 5.8mm x 13mm on superior extension part of the mass measured on coronal scan.The inner ear structures, cochlea, vestibule, semicircular labyrinth are normal. The right internal auditory canal is normal with delineation of the facial, cochlear and vestibular nerves. Brain MRI:The ventricles, cerebral sulci and cisterns are symmetric and unremarkable. There is no supratentorial mass, mass effect, edema, midline shift, intra or extra-axial fluid collection/hemorrhage. There is no evidence of restricted diffusion/acute ischemia. The midline structures and cranial-cervical junction are normal. Normal flow voids are identified in the major intracranial vessels. The paranasal sinuses and mastoid air cells are clear.
1. Post left retrosigmoid craniectomy related changes with residual masses around the left IAC with both well enhancing and not well enhancing extra axial mass lesions mixed with T1 and T2 low signal lesions as described above.2. No evidence of acute ischemic or hemorrhagic lesion.3. Encephalomalacia on the anterior and inferior aspect of the left cerebellum (AICA territory).