After having carefully evaluated the location of a mass, which often is the most crucial part of interpretation (e.g. in this case, realizing that the mass is not related to vestibulocochlear nerve excludes and acoustic schwannoma form the differential), one is left with a variety of diagnoses and other factors come into play. How much weight to put on demographic information (e.g. prior medical history, ancestry, travel) and how much to rely on more generic stats is a challenge and tests Bayesian thinking.  In this case, the fact that the patient was a recent immigrant from Africa was a red-herring.