Antrolith

Definition: A calcification within the maxillary sinus, formed from long-standing mucus or foreign bodies, including tooth fragments.

Radiographic Features:

  • Location: Within maxillary sinuses
  • Edge: Well-defined, smooth or irregular outline
  • Shape: Round or ovoid
  • Internal structure:
    • Radiopaque
    • May show ‘laminated’ appearance (radiopaque and radiolucent bands)
  • Other: None specific
  • Number: May be single or multiple

Key points:

  • Formed by gradual calcium salt deposition
  • ‘Laminated’ appearance resembles layers of an onion
  • Can vary in size
  • May be asymptomatic or cause sinus-related symptoms

Clinical significance:

  • Usually an incidental finding
  • Can cause sinusitis or other sinus-related symptoms if large
  • May require removal if symptomatic or interfering with sinus function
  • Important to differentiate from other sinus pathologies

Note: Evaluate multiple images to ensure the radiopacity is not attached to the sinus border. If it appears attached in multiple views, consider antral exostosis/antral projection as a differential diagnosis.