There may be no LaTeX in Microsoft Word, but people working on its equation editor seem to be very much aware of LaTeX. Take a look at Murray Sargent's blog: https://blogs.msdn.microsoft.com/murrays/
Most annoyingly to me, \frac and other commands not directly associated with a symbol do not seem to be supported. That said, it's still extremely useful for my narrow use case (high school teacher semifluent in TeX with colleagues who are not).
edit: Also, it supports more symbols than its GUI provides; the only way to get the arc symbol that Geometry teachers like is to use \overparen.