  Dissimilarities in the spatial distribution of small (micron-size) and large
(millimeter-size) dust grains at the cavity edge of transition disks have been
recently pointed out and are now under debate. We obtained VLT-NACO near-IR
polarimetric observations of SAO 206462 (HD135344B). The disk around the star
shows very complex structures, such as dips and spirals. We also find an inner
cavity much smaller than what inferred from sub-mm images. The interaction
between disk and orbiting companion(s) may explain this discrepancy.
