  We analytically compute two-loop Yukawa corrections to Higgs boson pair
production in the high-energy limit. Such corrections are generated by an
exchange of a Higgs boson between the virtual top quark lines. We propose two
approaches to obtain expansions of the massive two-loop box integrals and show
that precise results are obtained for transverse momenta of the Higgs bosons
above about 150 GeV. We discuss in detail the computation of all 140 master
integrals and present analytic results.
