Langerhans cell histiocytosis of the lumbar spine

Langerhans cell histiocytoses (LCH) is a condition that primarily involves the skeleton, and the lesions are typically seen as lytic on radiographs. The appearance of LCH lesions on skeletal scintigraphs varies from photopenic to markedly osteoblastic. A 10-year-old boy had a 6-week history of low back pain. Slight obliteration of normal lumbar lordosis was the only significant finding on physical examination. Conventional radiographs of the lumbar spine showed a defect in the spinous process of the L2 vertebral body. Bone scintigraphy revealed a marked osteoblastic reaction in the posterior elements and spinous process of the L2 vertebra, suggesting an aggressive malignant bone tumor or infection. Computed tomography (CT) and magnetic resonance imaging (MRI) confirmed significant erosion of the posterior elements of the L2 vertebra, with a soft tissue mass in the area of the bone defect. Biopsy revealed LCH. This case illustrates the destructive nature of LCH, particularly as seen on a CT scanning, and the highly vascular nature with marked osteoblastic reaction seen on bone scintigraphy. This case highlights the variable appearance of LCH on bone scintigraphy.