Orbital and craniofacial involvement of aneurysmal bone cyst: A rare case report

Aneurysmal bone cyst (ABC) is a rare, benign but expansile osteolytic lesion that most commonly involves the long bones, vertebrae, and cranial bones. Orbital and craniofacial involvement is exceptionally rare and may present with rapidly progressive symptoms due to mass effect. We report the case of a 15-year-old patient who presented with a progressive swelling extending from the nasal cavity to the right orbit and frontal region over a period of 3 months. Ophthalmic examination revealed proptosis, restricted ocular motility, and decreased visual acuity in the right eye. Imaging studies, including computed tomography and magnetic resonance imaging, demonstrated a multiloculated, cystic, and solid lesion with fluid–fluid levels, destroying the frontal, ethmoidal, maxillary, and orbital bones, and displacing the right globe laterally. Multidisciplinary surgical excision via fronto-orbital craniotomy was performed, and histopathological evaluation confirmed the diagnosis of ABC. Postoperatively, significant regression of proptosis and improvement in visual acuity were observed. Orbital involvement of ABC is extremely rare but should be considered in the differential diagnosis of destructive craniofacial masses in children and adolescents. Radiological identification of characteristic fluid–fluid levels combined with histopathological confirmation is essential for accurate diagnosis. Early surgical intervention can prevent further visual deterioration and provide favorable functional and cosmetic outcomes.

Keywords: Aneurysmal bone cyst, craniofacial involvement, orbit, proptosis.