To what object is the appearance of this mass (with one component in the CPA and the other in Meckle's cave) likened to?
To a dumbbell.
What is the most likely diagnosis? What is the main differential?
Trigeminal schwannoma is most likely. A meningioma could have similar appearances.
What features favour a trigeminal schwannoma over a meningioma?
Dumbbell configuration; high T2 signal; heterogeneous enhancement.
What should be carefully sought in the remainder of the scan, and what would be the implication if found?
Other schwannomas (especially acoustic schwannomas) and meningiomas. Presence of either would raise the suspicion of NF2.
MRI through the brain demonstrates a large cerebellopontine angle mass on the right, with a component extending anteriorly into Meckle's cave. The mass is heterogenous on all sequences, and relatively high signal on T2, with avid contrast enhancement, and areas which are presumably cystic.