What is the diagnosis of a periosteal tear called?

Diagnosis of Periosteal Tear

The diagnosis of a periosteal tear or periosteal reaction is called "periostitis" or more specifically "periostitis ossificans" when new bone formation occurs beneath the periosteum. 1, 2

Terminology and Classification

Periostitis refers to inflammation of the periosteum that results in reactive new bone formation. The specific terminology depends on the underlying cause and imaging appearance:

• Periostitis ossificans (also known as Garré osteomyelitis): A chronic form characterized by new bone formation under the periosteum, typically in response to chronic inflammation or infection 1, 2
• Reactive periostitis: A general term for periosteal reaction to various stimuli including trauma, infection, or other irritation 3
• Periosteal reaction: The radiographic term describing the imaging appearance of periosteal thickening or elevation 4, 5

Clinical Context and Differential Diagnosis

The term used depends critically on the underlying etiology, as periosteal reactions are nonspecific findings that can result from multiple causes 3, 4:

Infectious Causes

• Osteomyelitis: Periosteal thickening/elevation appears as a relatively late finding on conventional radiographs, though it's an early finding on MRI 3, 5
• Subperiosteal abscess: A specific complication of pyogenic osteomyelitis requiring surgical drainage 3

Non-Infectious Causes

• Stress fractures: Present with periosteal thickening as an early radiographic finding 4
• Trauma: Can cause periosteal reactions without infection 6
• Vasculitis: Rare manifestation, as in IgA vasculitis 6
• Malignancy: Primary bone tumors (osteosarcoma) or metastatic disease may demonstrate periosteal reaction 4

Diagnostic Approach

When periosteal thickening or elevation is identified on imaging, the diagnosis requires integration of clinical context, imaging characteristics, and often tissue sampling 4, 7:

Initial Imaging Findings

• X-ray appearance: Shows periosteal thickening/elevation, which may appear as single lamellar, spiculated, or "onion skin" patterns 1, 6
• Early vs. late findings: Periosteal reactions appear earlier in the disease course than frank bone destruction 5

Advanced Imaging for Characterization

• MRI: Demonstrates periostitis with high sensitivity (90-98%) and shows associated bone marrow edema and soft tissue involvement 3
• CT: Better for detecting cortical irregularities, erosions, and the specific pattern of periosteal reaction 3, 8

Definitive Diagnosis

Biopsy is often necessary to distinguish between infectious, inflammatory, and neoplastic causes, particularly when malignancy cannot be excluded 4, 7. Periosteal biopsy can establish whether the reaction is secondary (periostitis ossificans) or represents a primary periosteal lesion 7.

Common Pitfalls to Avoid

• Do not assume all periosteal reactions are infectious: The finding is nonspecific and can be associated with pressure-related bone changes, fractures, soft tissue infections, and malignancy 3, 4
• Do not rely on periosteal reaction alone for diagnosis: Clinical examination findings have low sensitivity (22-33%) for diagnosing underlying osteomyelitis 3
• Do not delay advanced imaging in suspicious cases: Normal X-rays do not exclude serious pathology, and persistent symptoms require MRI evaluation 4, 5
• In patients under 40 with periosteal thickening plus bone destruction or soft tissue mass: Urgent referral to a bone sarcoma center is required to exclude malignancy 4