We present observations of three protoplanetary disks in scattered light around M-type stars in the Upper Scorpius OB association using the STIS instrument on the Hubble Space Telescope. These disks have all been previously detected with ALMA, and one of them has never previously been imaged at scattered light wavelengths. We process our images using Reference Differential Imaging, comparing and contrasting three reduction techniques - classical subtraction, Karhunen-Loeve Image Projection and Non-Negative Matrix Factorisation, selecting the classical method as the most reliable of the three. Of our three disks, one is a non-detection, and the other two are tentative detections. These two detections are shown to be consistent when the reference star or reduction method used is varied, and both detections exhibit structure out to large angular separations not seen in our non-detection. The extended structures present in these two disks have never been previously observed at any wavelength, and may indicate ongoing disk dispersal via stellar winds.