Thoracic aneurysmal bone cyst secondary to osteoblastoma: unique surgical management. Illustrative case.

Background: Aneurysmal bone cysts (ABCs) are rare, benign, yet locally aggressive lesions that contain blood-filled channels that rarely occur in the thoracic spine of adults. The literature on the treatment of spinal ABCs is sparse, but the consensus is to achieve gross-total resection (GTR) due to these lesions being locally aggressive and to prevent recurrence.

Observations: This report describes a 35-year-old female admitted with back pain and right T5 dermatome radiculopathy without any inciting events. Magnetic resonance imaging revealed a 3.0 × 4.3 × 4.0-cm solid, enhancing, multicystic lesion with multiple fluid levels centered in the right posteromedial chest wall, involving the right fifth rib and costovertebral junction. Because of the high suspicion for an ABC, later found to be secondary to an osteoblastoma, surgical intervention was planned via preoperative embolization and T4-6 fusion with right T5 laminectomy and costotransversectomy to obtain GTR.

Lessons: This case of an ABC secondary to osteoblastoma of the spine showcases a strategy for unique surgical management, given the limited information on treatment considerations for secondary ABCs. https://thejns.org/doi/10.3171/CASE24471.