Originally Posted by sun surfer
I would not use the term "prologue" in a TOC for an epigraph; it's not the same thing. Nor would I go with "preface" or really any of the others for the same reason.
In my opinion, it's an epigraph, so if you're going to have it labelled in a TOC, that's the appropriate word to use.
In fiction an epigraph is usually a fragment that sets the tone/scene for what is to follow, whereas a Prologue is a self-contained scene that precedes the narrative.
In every book I've seen Prologue and Epilogue go into the TOC but epigraphs don't.
Probably why the term isn't in common usage.