  Diffractive deeply inelastic scattering from a hadron is described in terms
of diffractive quark and gluon distributions. If the transverse size of the
hadronic state is sufficiently small, these distributions are calculable using
perturbation theory. We present such a calculation and discuss the underlying
dynamics. We comment on the relation between this dynamics and the pattern of
scaling violation observed in the hard diffraction of large-size states at
HERA.
