Type:
Educational Exhibit
Keywords:
Oncology, MR, Imaging sequences, Neoplasia
Authors:
S. Kadri1, S. Arooj2, A. Ghulam Mohammad 2, N. Ahmed2, F. ahmad3, T. Mahmood2; 1Karachi, karachi/PK, 2Karachi/PK, 3Lahore/PK
DOI:
10.26044/ecr2019/C-3274
Findings and procedure details
Acoustic neuromas and meningiomas represent the great majority of CP angle.
The tumors usually arise from the cerebellopontine cistern and other structures like arachnoid cyst,
schwannoma,
aneurysm/ AVM,other meningeal lesions or from embryologic remnants like epidermoid cyst,
dermoid cyst,
lipoma.
Tumors can also invade the CPA by extension from the petrous bone or skull base in paraganglioma,
chondromatous tumors and chordoma. the other differential of CPA lesions can be secondary to an exophytic brainstem or ventricular tumor like metastasis,
glioma,
choroid plexus papilloma,lymphoma,hemangioblastoma,
ependymoma,
medulloblastoma.
MRI,
1.5 T system with protocols for the cerebellopontine angle evaluation usually done .
Additional imaging were also available,
according to the case.
The diagnosis of masses in CP angle can be simplified by using morphologic and enhancement characteristics .E.g Vestibular Schwannomas are enhancing,
round masses,
most commonly arising from the vestibular nerve near the porus acusticus and associated with enlargement of the internal auditory canal.
In cases of VII nerve schwannoma,
enhancing component extend along VII nerve where as V nerve schwannomamay involve any part of V nerve complex but mostly are in Meckel's cave.
Meningiomas are enhancing lesions with a broad attachment to the tentorium or petrous dura mater having dural tail.
Arachnoid cyst shows CSF signals ,
AVM shows prominent flow voids on MRI ,
Epidermoid cysts are nonenhancing masses that have undulating margins,
molding their shape to conform to the adjacent structures with restriction on DWI.
Lipoma usually has homogenous fat signals and dermoid has mixed fat signals with calcification.
Paragngliomas arises at jugular foramen or middle ear reaches to cp angle with characterstic salt and pepper appearance.