Hot massive stars constitute an important class of objects among stellar populations. Diffraction limited high dynamic imaging (HDI) with 8-10 m class telescopes of fine structures which often characterize their extended nebulosities can trace back the history of their mass-loss, therefore the evolution of the central star across the HRD. Since these stars are among the most luminous stars and display unique emission spectral features in galaxies at high redshift, they can serve as natural candles to estimate cosmological distances through the Wind-momentum Luminosity Relation (WLR, Kudritzki et al. 2000). In this paper I develop the context of massive stars HDI and derive some general instrumental specifications for coronagraphic adaptive optics.