  Mrk 477 is the closest type-2 quasar (QSO2), at a distance of 163 Mpc. This
makes it an ideal laboratory for studying the interplay between nuclear
activity and star formation with a great level of detail and signal-to-noise.
In this Letter we present new mid-infrared (mid-IR) imaging and spectroscopic
data with an angular resolution of 0.4 arcsec (~300 pc) obtained with the Gran
Telescopio Canarias (GTC) instrument CanariCam. The N-band (8-13 micron)
spectrum of the central ~400 pc of the galaxy reveals [S IV]10.51 micron
emission, but no 8.6 or 11.3 micron PAH features, which are commonly used as
tracers of recent star formation. This is in stark contrast with the presence
of a nuclear starburst of ~300 pc in size, an age of 6 Myr, and a mass of
1.1x10^8 Msun, as constrained from ultraviolet Hubble Space Telescope
observations. Considering this, we argue that even the more resilient, neutral
molecules that mainly produce the 11.3 micron PAH band are most likely being
destroyed in the vicinity of the active nucleus despite the relatively large
X-ray column density, of log N_H=23.5 cm^-2, and modest X-ray luminosity, of
1.5x10^43 erg/s. This highlights the importance of being cautious when using
PAH features as star formation tracers in the central region of galaxies to
evaluate the impact of feedback from active galactic nuclei.
