Things are are not always easy with just 1 slice. The key to this one is the 4th ventricle - effaced from the left. So there is a left cerebellopontine angle mass. And always ask why am I being shown 2 pictures. The bone window image shows enlargement of the left porus acousticus of the IAC (so called trumpeted internal acustic meatus sign )

Answer: Left vestibular (acoustic) schwannoma - 80% of CPA masses. How about a better view? yep, same patient.