Start practicing

Radiology · patient case question

What is this, and what does it require?

Patient case: A dome on the floor of the sinus

Patient: Male, 41 years old

Chief Complaint: Attends for assessment before an implant to replace #14.

Background: Healthy, non-smoker. No nasal obstruction, no facial pain, no discharge, no history of sinus disease.

Vital Signs: BP 124/76 mmHg · HR 70 bpm · afebrile

Findings: The panoramic radiograph shows a smooth, well-defined, DOME-SHAPED radiopacity rising from the FLOOR of the right maxillary sinus. The remaining sinus is well aerated. All adjacent teeth respond normally to cold and have intact lamina dura.

  1. An antral malignancy — urgent referral
  2. A periapical cyst displacing into the sinus — endodontic treatment
  3. An antral mucous retention pseudocyst — no treatment
  4. Odontogenic sinusitis — drainage and antibiotics
Show answer and explanation

Correct answer: C. An antral mucous retention pseudocyst — no treatment

  • A. An antral malignancy destroys the bony walls of the sinus, has ill-defined margins, and produces symptoms — paraesthesia, epistaxis, nasal obstruction, loosening teeth or facial swelling. A smooth dome on an intact sinus floor is not that.
  • B. A periapical cyst projecting into the antrum would be CONTINUOUS with the apex of a NON-VITAL tooth and would show loss of the lamina dura at that apex. Every adjacent tooth here is vital with intact lamina dura, which excludes it.
  • C. CORRECT. The ANTRAL MUCOUS RETENTION PSEUDOCYST — also called an antral pseudocyst or mucosal antral cyst — is among the commonest incidental panoramic findings, reported in roughly 2–10% of patients. It is an accumulation of inflammatory exudate lifting the sinus lining, and it is a PSEUDOcyst because it has NO EPITHELIAL LINING. Its features are exactly those described: smooth, well-defined, DOME-SHAPED, rising from the FLOOR of the antrum, asymptomatic, and frequently changing in size or resolving spontaneously on later films. It requires NO treatment.
  • D. Odontogenic sinusitis produces generalised mucosal thickening or an air-fluid level, together with symptoms — facial pain, nasal discharge, congestion — and an identifiable odontogenic source. This patient has a well-aerated sinus and no symptoms at all.

Note: Two practical points for this patient. The pseudocyst does NOT preclude implant placement or a sinus lift, but a large one may warrant ENT opinion beforehand, because grafting can displace it and obstruct the ostium. And distinguish it from a true MUCOCELE of the sinus, which is an entirely different problem — it fills and EXPANDS the whole sinus, thins and displaces the bony walls, and does require surgical management.

Practice Radiology questions Radiology study notes

More Radiology practice questions