Aneurysmal bone cyst of thoracic spine mimicking spinal tuberculosis.

A 22-year-old female presented to our services with back pain and paraparesis for 11 months. She was earlier diagnosed with tuberculosis of spine, and antitubercular chemotherapy was started. However her condition had worsened. Plain and contrast-enhanced computed tomography scans of the thorax and magnetic resonance imaging of the thoracic spine showed heterogenous, lytic, expansile lesion involving third thoracic vertebra with epidural extension and large bilateral paraspinal and mediastinal components. Multiple variably sized loculations with fluid-fluid levels were seen within the lesion. These imaging findings suggestive of aneurysmal bone cyst of thoracic spine were compared with the findings seen 11 months earlier, which were mistaken for spinal tuberculosis. Histopathology confirmed the diagnosis of aneurysmal bone cyst. The imaging features, diagnostic challenges and the lessons learned have been briefly discussed.