A 49-year-old woman presented with 6 months of progressive left superior sulcus hollowing unassociated with diplopia, trauma, sinus disease, or use of prostaglandin agonist drops. Examination revealed left superior sulcus deepening with 1.5-mm inferior displacement and 1-mm enophthalmos of the left eye (Figure A). A computed tomographic scan revealed left maxillary sinus opacification, obstruction of the ostium, orbital floor downward bowing, and thickening and calcific excrescences of the maxillary sinus walls and roof (Figure B).