Preschooler with worsening back pain for 3 weeks and then refusal to walk

Radiograph and MRI of Langerhans cell histiocytosis of the spine
Lateral radiograph of the lumbar spine shows loss of height of the L1 vertebral body. Coronal and sagittal T1 MRI with contrast of the lumbar spine shows flattening (vertebra plana) and enhancement of the L1 vertebral body with a small enhancing right sided paravertebral mass.

The diagnosis was Langerhans cell histiocytosis of the spine.