Spinal Langerhans Cell Histiocytosis (LCH)

Figure 1: Tc-99m MDP bone scan (posterior image) shows a focus of increased activity at L2 vertebral body in a 24-year-old woman presenting with back pain.

Figures 2&3: Axial GRE T2W and sagittal post-contrast T1W MR images show a round focus of bone destruction surrounded by bone marrow edema and enhancement of L2 body, sparing the posterior elements. 

Facts: LCH

• Rare, benign disorder of unknown etiology comprises of eosinophilic granuloma (unifocal), Hand-Schuller-Christian disease (multifocal) and Letterer-Siwe disease (disseminated variant) - these are different manifestations of a same disease
• Clonal proliferation of Langerhans cells
• Peak incidence 5-10 years but there is a shift toward younger children

Spinal LCH

• Vertebral involvement in 8-25% of cases
• Thoracic > cervical, lumbar
• Vertebral body >> posterior elements
• Solitary, well-defined osteolytic lesion with scalloped borders eventually progresses to collapse and a classic "vertebra plana"
• Typically single vertebral body involved. Disc spaces spared
• Soft tissue mass suggests more aggressive course

Main Imaging Differentials of Spinal LCH

• Osteomyelitis
• Ewing sarcoma
• Leukemia, lymphoma, metastatic neuroblastoma

Reference:
Hosalkar HS, Greenberg JS, Wells L, Dormans JP. Isolated Langerhans Cell Histiocytosis of the T12 vertebra in an adolescent. Am J Orthop 2007;36: E21-E24.