RESUMEN
BACKGROUND: Aneurysmal bone cysts are benign bone lesions affecting long bones and vertebrae; only 2%-6% have cranial involvement, and even fewer show sphenoid or intraorbital involvement. Gross total resection is the treatment of choice. CASE DESCRIPTION: A 10-month-old girl presented with unilateral proptosis and no neurologic deficits. Imaging studies revealed an extensive right-sided skull base cystic lesion centered on the sphenoid wing with extension into the orbit anteriorly and the pterygoid plates inferiorly. She underwent a modified osteoplastic orbitozygomatic craniotomy for resection of the extradural tumor. Postoperative imaging showed successful decompression of the intraorbital contents with no residual tumor. She remained neurologically intact and was discharged on postoperative day 2. Histologic examination revealed the lesion to be consistent with an aneurysmal bone cyst. At 3-month follow-up, her proptosis had resolved, neurologic examination was nonfocal, and there was no radiographic evidence of recurrence. CONCLUSIONS: To our knowledge, this is the youngest patient reported to have a spheno-orbital aneurysmal bone cyst. Such lesions in this age group present practical management challenges. By using a modified osteoplastic orbitozygomatic craniotomy, we achieved a gross total resection with minimal brain retraction, avoided the need for plating and suturing at the orbital rim, maintained a vascularized bone flap that is less susceptible to infection, and maintained normal temporalis muscle anatomy with excellent cosmetic results.