Why not?
356.10 Uses Permitted.
(7) For encasement in concrete where listed for direct burial and installed in compliance with 356.42.
Not really relevant but ...
356.42 Couplings and Connectors.
Only fittings listed for use with LFNC shall be used. Angle connectors shall not be used for concealed raceway installations. Straight LFNC fittings are permitted for direct burial or encasement in concrete.
They usually use smurf here if it can be called interior (like the back of a pancake) but I see LFNC if there is a question.
