[Orbital aneurysmal bone cyst in a 2-year-old child]

Area of Science:

• Pediatric Oncology
• Ophthalmology
• Skeletal Pathology

Background:

• Aneurysmal bone cysts (ABCs) are rare, benign, tumor-like lesions that can affect any part of the skeleton, predominantly in children and adolescents.
• While ABCs can occur anywhere, their presentation at the skull base in pediatric patients is exceptionally uncommon.

Observation:

• A 22-month-old male presented with sudden right eye proptosis.
• Radiological imaging revealed a cystic, well-defined, contrast-enhancing mass on the medial-cranial orbital wall, with early frontal skull base destruction.
• Histological examination of a biopsy from medial orbitotomy showed giant-cellular and fibrohistiocytic changes.

Findings:

• Definitive histological diagnosis post-excision confirmed an aneurysmal bone cyst.
• The lesion demonstrated aggressive, expansive growth, impacting the orbital wall and skull base.

Implications:

• Aneurysmal bone cysts should be considered in the differential diagnosis of orbital tumors in children, especially when aggressive growth is evident.
• Clinical and radiological findings alone are insufficient for diagnosis; early biopsy is crucial for accurate diagnosis, despite potential histological challenges.
• This case underscores the importance of considering rare diagnoses in pediatric orbital masses presenting with rapid progression.