Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

 

Overview

Vertebra plana refers to complete or near-complete collapse of a vertebral body, resulting in a flattened appearance.

• Classically associated with eosinophilic granuloma
• Represents a manifestation of Langerhans Cell Histiocytosis (LCH)
• Important because it can mimic multiple serious conditions

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Definition

• Vertebra plana:
  • Flattening of vertebral body
  • Loss of both anterior and posterior height

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Also Known As

• Pancake vertebra
• Flattened vertebra

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Eosinophilic Granuloma (Underlying Cause)

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Definition

• Tumor-like lesion due to proliferation of Langerhans cells (histiocytes)
• Part of the spectrum of Langerhans Cell Histiocytosis

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Key Characteristic

• Benign but may appear aggressive on imaging

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Distribution of Eosinophilic Granuloma

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Common Sites

• Skull
• Spine
• Long bones

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Other Possible Involvement

• Skin
• Visceral organs

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Clinical Insight

• Known as the “great imitator” due to varied presentation

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Differential Diagnosis

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Eosinophilic granuloma may mimic:

• Osteomyelitis
• Ewing sarcoma
• Leukemia
• Lymphoma
• Fibrous dysplasia

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Typical Features of Vertebra Plana

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Spinal Involvement

• Most commonly affects:
  • Thoracic spine

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Pattern

• Usually involves a single vertebra

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Important Radiological Features

• Vertebral body collapse
• Preserved intervertebral disc height
• Posterior elements intact

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Age-Based Causes of Vertebral Collapse

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In Children (2–10 years)

• Most common cause:
  • Eosinophilic granuloma

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In Elderly

• Most common cause:
  • Osteoporosis

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Clinical Presentation

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Symptoms

• Back pain
• Neck pain
• Spinal deformity (kyphosis)

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Neurological Features

• May occur if:
  • Spinal cord compression develops

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Multiple Vertebral Involvement

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If more than one vertebra is involved, consider:

• Lymphoma
• Gaucher disease
• Mucopolysaccharidosis
• Metastatic disease

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Radiological Features

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Key Findings

• Focal bone destruction
• Vertebral body collapse
• Preserved disc spaces
• Minimal posterior element involvement

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Important Point

• Appears aggressive
• But usually benign and self-limiting

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Histology

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Langerhans Cells

• Large histiocytes with:
  • Abundant cytoplasm
  • Coffee-bean shaped nuclei
  • Nuclear grooves

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Eosinophils

• Bilobed nuclei
• Eosinophilic cytoplasm
• Present in large numbers

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Birbeck Granules

• Seen on electron microscopy
• Tennis racket-shaped structures
• Diagnostic of Langerhans cells

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Differentiation from Other Conditions

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Ewing Sarcoma

• Small round blue cells

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Osteomyelitis

• Mixed inflammatory infiltrate
• Signs of infection

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Natural History

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• Typically:
  • Benign
  • Self-limiting
  • Spontaneously resolving

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Recovery

• Vertebral body may regain:
  • Up to ~50% of original height over time

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Management

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1. Conservative Treatment (Most Cases)

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Approach

• Observation
• Regular follow-up

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Supportive Measures

• Spinal bracing:
  • Prevent deformity
  • Aid healing

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2. Surgical Treatment

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Indications (~10%)

• Severe spinal deformity
• Neurological deficit

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3. Radiotherapy

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Indications

• Neurological compression
• When surgery is not feasible

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Dose

• Low-dose radiation (~500–900 cGy)

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Key Takeaways

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• Vertebra plana is most commonly caused by eosinophilic granuloma in children
• It is a benign, self-limiting condition despite aggressive imaging appearance
• Single vertebra involvement + preserved disc space is characteristic
• Always consider differentials in multiple vertebral collapse
• Most cases are treated conservatively with good outcomes