Aneurysmal bone cysts (ABCs) are benign, expansile, nonneoplastic osteolytic lesions that may originate of any site of skeleton.
They represent 1%-2% of primary bone tumors.
The spine can be affect up to 30% of the cases, leading to pain, neurological deficits, and pathological fractures in symptomatic patients. The incidence of craniocervical (occipito-C1-2) occurrence is not known.
Cranial ABCs are even more rare and represent 3%-6% of these unique lesions.
Do multiple fluid-fluid levels on MRI always reveal primary benign aneurysmal bone cyst? 1).
An 11-year-old girl with a lesion in the posterior aspect of the atlas, and a 28-year-old man with an important hydrocephalus and a posterior expansible lesion on the left side of his posterior fossa. Total resection was achieved on both lesions, with no surgical morbidity. Even though ABCs are nonneoplastic lesions, subtotal resection is associated with early recurrence. The knowledge of the anatomy of the region in order to achieve the occlusion of arterial feeders prior to surgical resection itself is the key point of the surgical strategy 2).
The case of a 3-year-old girl who presented with an acute posterior fossa epidural hematoma after minor trauma. Imaging workup revealed a previously undiagnosed suboccipital ABC that appeared to have ruptured as a result of her trauma, leading to a life-threatening hemorrhage. To the authors' knowledge, a ruptured ABC has never before been presented in the pediatric literature. In this case report, the authors review the imaging findings, natural history, clinical course, and treatment of these rare lesions 3).