Definition: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: A patient with a mobile schwannoma of the cauda equina is described. There was considerable discrepancy between the localization of the tumor at myelography and the findings at both initial surgery and repeat myelography, confirmed by definitive surgery. Such mobility is rare, but should be kept in mind when surgery is performed for a tumor of the cauda equina.

Human