Bony sequestrum: a radiologic review

Area of Science:

• Radiology
• Pathology
• Oncology

Background:

• A bony sequestrum is pathologically defined as devitalized bone separated by necrosis.
• Radiologically, a sequestrum is an image of calcification within a lucent lesion, distinct from surrounding bone.
• The term "button sequestrum" specifically applies to calvarial lesions.

Purpose of the Study:

• To differentiate the pathological and radiological definitions of a bony sequestrum.
• To outline the various conditions that can present with a bony sequestrum on imaging.
• To emphasize the importance of clinical and radiological correlation in diagnosing sequestrum-containing lesions.

Main Methods:

• Review of radiological and pathological definitions of bony sequestrum.
• Analysis of imaging findings in conditions presenting with sequestra.
• Correlation of imaging features with clinical data.

Main Results:

• Conditions like osteomyelitis and tuberculosis are common causes of bony sequestra.
• Other differential diagnoses include radiation necrosis, eosinophilic granuloma, and various bone tumors (primary and metastatic).
• Some primary bone tumors mineralize, mimicking sequestra, including osteoid osteomas, chondroblastomas, and fibrous tumors.

Conclusions:

• Diverse pathologies can manifest as osteolytic lesions with central calcifications resembling a sequestrum.
• Distinguishing between these conditions relies on a comprehensive evaluation of the sequestrum's characteristics and associated clinical findings.