Maxillary sinus radiology

1. Inflammatory

a. Retention cyst – Mucosal gland blocked

NB: Antral cysts

  • From mucous glands:
    • Asymptomatic
    • Disappear spontaneously
  • Odontogenic cysts:


b. Mucocele

  • Sinus opening in nasal passage blocked (allergy/cold)
  • Sinus filled with thick viscous fluid
  • Radiology: Clouding/opacification of whole sinus, sclerotic border still intact
  • If bacterial infection – destroy sclerotic wall


c. Sinusitis

  • Acute x chronic x hypersensitive
  • Rhinogenic x odontogenic
  • Periapical inflammation of premolar or molar
  • Long oroantral communication
  • Pain + percussion sensitivity
  • Histology:
    • Respiratory epithelium → squamous metaplasia
    • Thickened basal membrane
    • Infiltrate:
      • Acute – neutrophils
      • Chronic – lymphocytes + plasma cells
      • Hypersensitive – eosinophils
  • Radiology
    • Mucosa lining thickened – opaque thickening on sclerotic border
    • Long standing – forms polyps (sessile/pedunculated) within sinus
    • Picture


d. Pneumatization

  • Sinus enlarges :
    • Edentulous
    • Chronic recurrent sinusitis
  • Roots may look like are in sinus
  • Enlarging sinus develops compartments


e. Fungal infection

  • Aspergillus/mucor
  • Grow in nasal passage and sinus of immune compromised
  • Bone destruction, sclerotic border disappear
  • Differential diagnosis: Sinus carcinoma


f. Mucositis

  • Sinus mucosa thickens due to long standing periapical infection/unsuccessful RCT


2. Foreign bodies in sinus

  • Displaced root fragments in antrum after unsuccessful extraction + form oroantral fistula
  • External objects inhaled into sinus
  • Foreign bodies may calcify – laminated opacities in sinus (anthrolith) or nasal passage (rhinolith)

Oroantral communication

  • After extraction of premolar or molar
  • Nose blowing test
  • Root or tooth in sinus
  • Prolapse of antral mucosa


3. Sinus fracture

  • Le Fort fracture of lateral sinus wall
  • Blow out fracture of ventral orbital wall:
    • Trap door sign – fracture wall bone fragments project down from roof of sinus
    • Fluid level in sinus
    • Polyp like mass hanging from roof of sinus


4. Sinus neoplasia

a. Sinus osteoma – Well circumscribed opacity in sinus

b. Giant cemento-ossifying fibroma – enlarges and obliterated sinus

c. Sinus carcinoma – destroy sinus wall, opacification of sinus

d. Others:

  • Squamous cell carcinoma
  • Advanced stage – local spread
  • Nose obstruction, nose bleeding
  • Paresthesia of infraorbital nerve
  • Visual disturbances
  • Poor prognosis