Radiology · patient case question
What is the most likely diagnosis?
Patient case: “I need some teeth here”
Patient: Female, 45 years old
Chief Complaint: “I need some teeth here.”
Background: Healthy, no medications, non-smoker. Teeth #19 and #20 were extracted more than ten years ago and never replaced. She has no pain and has never noticed a swelling.
Vital Signs: BP 118/76 mmHg · HR 70 bpm
Findings: The posterior left mandibular ridge is edentulous, firm and of normal contour with no expansion. In that edentulous bone the panoramic radiograph shows a well-defined lesion roughly 1.5 cm across, mixed radiolucent and radiopaque, with a thin radiolucent rim. The adjacent teeth are caries-free and respond normally to cold. The lesion was not present on a radiograph she brought from another office some years ago in the same location, which showed a lucency there.
Show answer and explanation
Correct answer: B. Focal cemento-osseous dysplasia
- A. A residual cyst is entirely RADIOLUCENT with a corticated border, left behind after extraction of the causative tooth. It does not develop internal opacity, and the mixed pattern here excludes it.
- B. CORRECT. FOCAL CEMENTO-OSSEOUS DYSPLASIA is a single-site fibro-osseous lesion arising from the periodontal ligament, with a strong predilection for the POSTERIOR MANDIBLE of middle-aged women — and it is very often discovered in an EDENTULOUS site during pre-prosthetic radiography, which is exactly this scenario. It is asymptomatic, non-expansile, under 2 cm, and matures through predictable stages: an early lucent phase, then a mixed phase, then a dense radiopaque phase with a thin peripheral lucent rim. Her older film showing a lucency in the same place documents that maturation. It needs no treatment — only periodic observation.
- C. Ossifying fibroma is a true benign NEOPLASM. It is well-demarcated but characteristically EXPANSILE, displacing roots and cortical plates as it grows, and it requires enucleation. A stable, non-expansile, incidentally found lesion does not fit.
- D. Condensing osteitis is purely SCLEROTIC — uniformly radiopaque with no lucent rim — and it is a reaction to low-grade pulpal inflammation, so it sits at the apex of a tooth with deep caries or a large restoration. There is no such tooth here, and the lesion is mixed rather than solidly opaque.
Note: Keep the three variants of cemento-osseous dysplasia straight. PERIAPICAL: anterior mandible, multiple teeth, and critically the teeth remain VITAL — pulp test before anyone starts a root canal. FOCAL: a single lesion, usually posterior mandible, often in an edentulous site. FLORID: multiquadrant and often extensive, most common in middle-aged Black women. All three are managed the same way — leave them alone.