Radiology · patient case question
What is the most likely diagnosis?
Patient case: Dome-shaped opacity in the floor of the maxillary sinus on a panoramic film
Patient: Female, 41 years old
Chief Complaint: “Nothing hurts — I came for my check-up.”
Background: No sinus symptoms, no facial pain, no nasal obstruction, no history of allergy or chronic sinusitis. No relevant medical history.
Vital Signs: BP 120/76 mmHg · HR 70 bpm
Findings: Panoramic radiograph shows a smooth, well-defined, DOME-SHAPED homogeneous soft tissue opacity arising from the FLOOR of the right maxillary sinus and projecting upward into the air space. The cortical floor of the sinus is intact beneath it. The adjacent posterior teeth are caries-free, restoration-free and respond normally to pulp testing, with no periapical radiolucency.
Show answer and explanation
Correct answer: A. Antral pseudocyst
- A. CORRECT. An ANTRAL PSEUDOCYST — also called a mucous retention pseudocyst or antral mucocele — is the classic incidental panoramic finding: a smooth, DOME-SHAPED, homogeneous soft tissue opacity rising from the sinus FLOOR with an intact cortical floor beneath it. It is an accumulation of inflammatory exudate lifting the sinus lining, and it is called a PSEUDOcyst because it has no epithelial lining. It is found in roughly 2–10% of panoramic films, is asymptomatic, requires NO treatment, and typically resolves on its own. Recognising it and leaving it alone is the whole point of the item.
- B. A cementoblastoma is a RADIOPAQUE mass FUSED TO A TOOTH ROOT, usually the mandibular first molar, surrounded by a thin radiolucent rim, and it is typically painful. It is attached to a root and would not float in the sinus air space.
- C. An odontogenic keratocyst is RADIOLUCENT, expands antero-posteriorly through the marrow space, and favours the posterior mandible and ramus.
- D. A complex odontoma is a densely RADIOPAQUE, disorganised mass of enamel and dentin with a radiolucent rim, sitting within bone. Its density approaches that of tooth structure, far greater than the soft tissue opacity described.
Note: Work through the sinus differential by SHAPE and by the state of the cortical floor. DOME-shaped soft tissue on an INTACT floor: antral pseudocyst — leave it. A UNIFORM opacification of the whole antrum with mucosal thickening and symptoms: sinusitis. A RADIOPAQUE mass with a cortical rim projecting into the antrum from below: an antrolith or a displaced root or tooth. DESTRUCTION of the cortical floor with an ill-defined margin: that is the one to worry about and to image with CBCT.