Summary:An otherwise healthy, 9-year-old boy had gradual onset of a mass deformity in the region of the left medial canthus with resulting superior and lateral globe displacement. Radiographic evaluation demonstrated an osteolytic, expansile lesion involving the bones of the ethmoid and maxillary sinuses. Combined anterior orbitotomy and nasal endoscopic surgical resection revealed additional involvement of the nasolacrimal sac wall. Histopathology was consistent with a giant cell reparative granuloma. The authors know of 15 case reports of sino-orbital giant cell reparative granulomas with ophthalmic manifestations; only 3 of these appeared in the ophthalmology literature. This case appears unique in that extension of the abnormal tissue into the nasolacrimal sac wall was demonstrated.