A panoramic radiograph is provided. Based on the image, what is the most likely diagnosis of the radiopaque lesion seen in the posterior maxilla?

Correct answer: D. Antral pseudocyst

• A. A complex odontoma appears as a radiopaque mass surrounded by a radiolucent rim; a compound odontoma shows multiple small tooth-like structures. Neither typically shows a dome-shaped maxillary sinus floor opacity.
• B. Cementoblastoma presents as a well-defined radiopaque mass attached to the ROOT of a tooth (most commonly mandibular first molar), surrounded by a thin radiolucent halo.
• C. Osteosarcoma presents as a destructive lesion with periosteal reaction ('sunburst' appearance) and moth-eaten bone destruction — not a dome-shaped sinus floor opacity.
• D. Correct. An antral pseudocyst (mucous retention pseudocyst) of the maxillary sinus appears as a dome-shaped, well-defined, homogeneous opacity at the floor of the maxillary sinus on panoramic radiograph. It is benign, asymptomatic, and usually requires no treatment.