Fig. 2

a T1-weighted MR image depicting the lesion at the time of first diagnosis, as a slightly hyperintense solid nodule (arrow) located on the floor of the right orbit. Part of the belly of the inferior rectus muscle appears compressed and displaced (arrowhead). Post-contrast images were not acquired in this MR examination. b Post-contrast fat-suppressed T1-weighted image shows the shrinkage of the lesion (arrow) 2 months after the initiation of orbital radiotherapy followed by fulvestrant-based hormonotherapy. c Post-contrast fat-suppressed T1-weighted image shows further shrinkage of the lesion (arrow) 17 months after the initiation of radiotherapy + hormone therapy. Palbociclib was also added between B and C, see text for details). Right inferior rectus muscle is not discernible in (b) and (c). The maximum dimension of the lesion was 14 mm in A, and decreased to 12 mm In B and to 7 mm in (c)