Giant Cell Tumor of Bone, Rare Inferior Orbit Location.

Giant cell tumor of bone (GCTB) typically presents in the epiphysis of long bones and occurs in the skull in less than 1% of cases. When GCTB is diagnosed in the skull, it is primarily seen in the temporal and sphenoid bones. GCTB is an osteoclastic stromal tumor that is locally aggressive and tends to recur. We present a case of a 43-year-old woman with slowly progressive, left-sided proptosis, eyelid swelling, photophobia, epiphora, and pressure sensation. Computed tomography and magnetic resonance imaging revealed an enhancing tumor in the left inferior orbit with infiltration into the maxillary sinus roof. Histological examination was conclusive for a giant cell tumor of the maxillary bone presenting as an inferior orbital mass. Gross total surgical resection was performed via an inferior anterior orbitotomy, and the patient had resolution of symptoms without recurrence in her postoperative course to date. This report contributes to the scarce literature available on this type of tumor of skull bones, specifically presenting the first case in the maxillary bone of the floor of the orbit.