Eggshell Calcification

General Considerations

• Calcification around the periphery of lymph nodes
• Reason for this pattern of calcification is not known
• Most commonly seen in silicosis and coal-worker's pneumoconiosis (3-6%)
• Also seen in sarcoid (5%)
• Rarely in post-irradiated Hodgkin disease, blastomycosis, scleroderma, amyloid and histoplasmosis

Imaging Findings

• Established criteria include
  • Calcification <2mm thick in the periphery of a lymph node
  • Ring-like shadow must be complete in at least one of the nodes involved
  • One of the nodes must be at least 1 cm in size
  • There may or may not be interior calcifications

Differential Diagnosis

• Pulmonary artery aneurysms
• Calcification of pulmonary arteries from prolonged pulmonary arterial hypertension

Eggshell Calcifications in Silicosis. The white arrows point to enlarged hilar lymph nodes with peripheral "eggshell" calcifications characteristic of either silicosis or sarcoidosis. This patient also has upper lobe fibrosis seen with silicosis and had a history of being a sandblaster.
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Eggshell Calcification of Lymph Nodes. Gross, B; Schneider, HJ and Proto, A. AJR:135, December 1980