Presentation
Right facial pain and numbness.
Patient Data
Right prepontine and cerebellopontine angle space occupying lesion. It shows a small enhancing solid component and large cystic component (tumor associated cyst). The solid component elicits lsointense signal on T1 and T2 WI with post contrast enhancement. It's surrounded by large cystic component eliciting low signal on T1 and high signal on FLAIR and T2 with no post contrast enhancement. The lesion measures collectively 3.1 x 3.4x 2.9 cm along its max Transverse, anteroposterior and craniocaudal dimension. It markedly indents the pons and the 4th ventricle with no hydrocephalic changes.
Radiological findings are suggestive of (preganglionic) trigeminal cystic schwannoma.
The forementioned cystic/solid complex lesion appears at the right prepontine/cerebellopontine angle, with the solid nodule appears isodense to the brain parenchyma.
Pathology after excision showed schwannoma with cystic changes.
Case Discussion
Radiological findings in this case were suggestive of (preganglionic) trigeminal schwannoma with large tumor associated cyst. That was confirmed pathologically.
Trigeminal schwannomas are encapsulated tumors composed of schwann cells. They are the second most common intracranial schwannoma, far less common than vestibular schwannoma, and has a predominantly benign growth.
They are divided into:
preganglionic: confined to the prepontine cistern and cerebellopontine angle cistern, like in our case
ganglionic: confined to Meckel cave
postganglionic: either confined to the cavernous sinus or extending through respective base of skull foramina, rarely confined to the extracranial compartment