The phrase "outlier cases" refers to unusual or exceptional situations or examples that are very different from the normal or average cases. Full definition
There have been people who've looked at outlier cases of Ingress. (fortune.com)
Throughout the week, Mike committed the Ecological Inference Fallacy, engaged in specification searching, generalized from outlier cases, and declared that we must prove a negative. (educationnext.org)
A few outlier cases that do not fit this pattern may get a disproportionate amount of attention, but the research consensus in favor of school choice as a general policy is clear and consistent.» (californiapolicycenter.org)