Definition: A localized collection of mucus in the paranasal sinuses, not a true cyst as it lacks an epithelial lining.
Radiographic Features:
- Location: Most common in maxillary sinuses, followed by sphenoid sinuses
- Edge: Well-defined
- Shape: Dome-shaped, attached to a sinus border
- Internal structure: Appears radiopaque (due to contrast with surrounding air)
- Other: None specific
- Number: May be single or multiple
Key points:
- Not a true cyst (lacks epithelial lining)
- Often asymptomatic and discovered incidentally
- May be associated with allergies, infection, or environmental irritants
- Appears radiopaque despite fluid content due to contrast with surrounding air
Clinical significance:
- Usually does not require treatment if asymptomatic
- May resolve spontaneously
- Can interfere with sinus procedures (e.g., sinus lift for dental implants)
- Important to differentiate from other sinus pathologies
Note: When evaluating a radiopaque area in the sinus, ensure the borders remain within the sinus boundaries. If borders appear to extend beyond the sinus, consider the possibility of superimposition from another structure.