Painless unilateral maxillary enlargement in a teenager
15-year-old female
§Chief complaint
Gradual swelling of the right cheek and upper jaw over 3 years
§Medical & dental history
- 01No café-au-lait macules, normal puberty — no evidence of McCune-Albright syndrome
- 02Mild displacement of 14-16 with no mobility; all vital
§Clinical examination
- 01Smooth, hard, non-tender fusiform expansion of the right maxilla blending into normal bone
- 02Mild obliteration of the buccal sulcus; palatal expansion
- 03Teeth vital, slight displacement without resorption
- 04No paraesthesia, no visual disturbance, no nasal obstruction
§ figuresFigures (5)
Fig. 1Medium power shot with the classic 'Chinese character' bone spicules.
“Bone FibrousDysplasia LP CTR” · Sarahkayb · CC BY-SA 4.0 · Wikimedia Commons
Fig. 2Immature bony trabeculae in a fibrous stroma.
“Bone FibrousDysplasia Jaw MP3 PA” · Sarahkayb · CC BY-SA 4.0 · Wikimedia Commons
Verified open-access images only, reproduced for education under their stated licences · no AI-generated or illustrative artwork · Fibrous Dysplasia figures pending faculty review.
§Differential diagnosis
§Final diagnosis
Monostotic fibrous dysplasia of the right maxilla
A ground-glass radiographic pattern with margins blending imperceptibly into normal bone, unilateral maxillary expansion in an adolescent, and histology showing irregular woven bone trabeculae in a cellular fibrous stroma without osteoblastic rimming, confirms fibrous dysplasia.
§Investigations
- 01Serum calcium, phosphate, ALP — ALP mildly raised during the active phase
- 02Incisional biopsy for histological confirmation
- 03Skeletal survey or bone scan to exclude polyostotic disease — negative
- 04Endocrine screen to exclude McCune-Albright syndrome
§Radiology
- 01CT — homogeneous ground-glass bone expanding the right maxilla with cortical thinning and blending margins
- 02OPG — loss of lamina dura and superior displacement of the maxillary sinus floor
§Treatment plan
- 01Observation during active growth; definitive contouring after skeletal maturity
- 02Conservative surgical recontouring for aesthetic or functional concerns
- 03Bisphosphonates considered for painful lesions
- 04Avoid radiotherapy — risk of malignant transformation
§Surgical procedure
- 01At age 18, conservative osseous recontouring via an intraoral vestibular approach with piezoelectric instruments
§Histopathology report
Irregular, curvilinear trabeculae of woven bone resembling Chinese characters within a moderately cellular fibrous stroma, without osteoblastic rimming; no atypia. Fibrous dysplasia.
§Follow-up & outcome
- 016-monthly clinical and photographic review during growth
- 02Post-operative 12 months — contour stable, no regrowth
- 03Long-term annual review
Outcome: Lesion stabilised after skeletal maturity; symmetrical facial contour achieved by recontouring.
§Discussion
- 01Fibrous dysplasia results from a post-zygotic GNAS1 mutation; monostotic disease is far more common than polyostotic.
- 02Most lesions stabilise after skeletal maturity, which is why definitive contouring is deferred.
- 03Malignant transformation is rare (under 1%) but rises sharply after radiotherapy.
§Clinical pearls / learning points
- 01Ground glass with blending borders = fibrous dysplasia; sharp borders = ossifying fibroma.
- 02Never irradiate fibrous dysplasia.
§Viva questions
Which gene is mutated?
GNAS1, a post-zygotic activating mutation causing mosaic disease.
What is McCune-Albright syndrome?
Polyostotic fibrous dysplasia with café-au-lait macules and endocrinopathies, classically precocious puberty.
§MCQs
Q1The classic radiographic appearance of fibrous dysplasia is:
Q2Histologically, fibrous dysplasia lacks:
§ evidenceReferences & Evidence
Current Classification
WHO Classification of Head and Neck Tumours
5th Edition — Volume 9
WHO Classification of Tumours Editorial Board · 2022
The authoritative international classification of head and neck, odontogenic and salivary gland tumours. Current terminology on this site follows this edition.
Evidence summary
Highest level of evidence linked to this page: WHO / Official Classification.
- L1 · Classification — 2
- L2 · Guideline — 1
- L6 · Textbook — 3
1 linked source was published from 2024 onwards. Where guidance is limited or contested, rely on the higher-level sources above rather than this summary. Educational use only — not a substitute for clinical judgement.
Content last reviewed
September 2026
Evidence last reviewed
September 2026
Next scheduled review
September 2027
Review status
EVIDENCE REVIEWED
Search latest PubMed evidence
Last literature search: 7 September 2026
Current Classification
WHO Classification of Tumours Editorial Board. IARC / World Health Organization · 2022
The authoritative international classification of head and neck, odontogenic and salivary gland tumours. Current terminology on this site follows this edition.
IARC / WHO. IARC · 2022
Continuously updated online edition of the WHO head and neck tumour classification.
Clinical Guidelines
Javaid MK, Boyce A, Appelman-Dijkstra N et al.. Orphanet journal of rare diseases · 2019 · 14(1):267
International consensus best-practice guidelines for fibrous dysplasia / McCune-Albright syndrome.
Histopathology References
Barnes L. CRC Press · 2008
Detailed histopathological reference for head and neck diagnostic criteria.
Textbook References
Neville BW, Damm DD, Allen CM et al.. Elsevier · 2024
Standard reference textbook of oral and maxillofacial pathology used throughout this atlas.
Rajendran R, Sivapathasundharam B. Elsevier · 2020
Undergraduate and postgraduate oral pathology textbook widely used in BDS and FCPS curricula.
Additional sources cited on this page
- WHO Classification of Head and Neck Tumours, 5th edition, 2022.
- MacDonald-Jankowski D. Fibrous dysplasia of the jaws. Dentomaxillofac Radiol.
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