Soap-bubble multilocular lesion expanding the mandible

§Chief complaint

Slowly enlarging hard swelling of the lower jaw for about 2 years

§Medical & dental history

• 01No systemic disease
• 02No previous jaw surgery
• 03Teeth in the region mobile but vital
• 04No history of trauma or infection

§Clinical examination

• 01Marked buccal and lingual bony expansion from 45 to the angle, 50 mm across
• 02Egg-shell crackling over the thinnest area; overlying mucosa intact
• 0346 and 47 grade II mobile, both vital
• 04Lower lip sensation normal, no cervical lymphadenopathy

§ figuresFigures (5)

Verified open-access images only, reproduced for education under their stated licences · no AI-generated or illustrative artwork · Ameloblastoma figures pending faculty review.

§Differential diagnosis

§Final diagnosis

Conventional (multicystic) ameloblastoma, follicular pattern

Gross buccolingual expansion with soap-bubble loculi, knife-edge root resorption and vital teeth is the classic pattern; incisional biopsy showing follicular islands with peripheral palisading, reverse nuclear polarity and stellate reticulum-like centres confirms it.

§Investigations

• 01Incisional biopsy under local anaesthesia
• 02Pulp testing — teeth vital, excluding an inflammatory origin
• 03Routine bloods and anaesthetic assessment for resection

§Radiology

• 01OPG — multilocular soap-bubble radiolucency 60 mm with knife-edge resorption of 46/47 roots
• 02CT with 3D reconstruction — buccal cortex perforated in two areas, inferior alveolar canal displaced, extent mapped for resection margins

§Treatment plan

• 01Segmental resection with 10-15 mm bony margins and one uninvolved anatomical barrier
• 02Immediate reconstruction with a reconstruction plate and free fibula flap
• 03Dental rehabilitation with implants once the graft consolidates

§Surgical procedure

• 01Submandibular approach with marginal mandibular nerve preservation
• 02Segmental resection from 44 to the sigmoid notch, margins confirmed by frozen section
• 03Free fibula osteocutaneous flap shaped in two segments, fixed with a load-bearing plate
• 04Microvascular anastomosis to the facial artery and vein

§Histopathology report

Follicular islands of odontogenic epithelium in a fibrous stroma; peripheral tall columnar cells with hyperchromatic nuclei polarised away from the basement membrane and subnuclear vacuolation, with loose stellate reticulum-like centres. Margins free of tumour. Conventional ameloblastoma.

§Follow-up & outcome

• 016 weeks — flap viable, occlusion maintained
• 026 months — bony union at both osteotomy sites
• 03Annual OPG surveillance for 10 years given late recurrence risk

Outcome: Disease-free at 4 years with an implant-supported prosthesis and acceptable facial contour.

§Discussion

• 01Conventional ameloblastoma is locally aggressive; conservative curettage recurs in 50-90% of cases, whereas resection with margins recurs in under 15%.
• 02BRAF V600E mutations are present in most mandibular ameloblastomas and open a targeted therapy option in unresectable disease.
• 03Recurrence may appear more than 10 years later, so lifelong surveillance is advised.

§Clinical pearls / learning points

• 01Knife-edge root resorption with soap-bubble loculi should raise ameloblastoma before any cyst.
• 02Enucleation is inadequate for the conventional multicystic variant.
• 03Unicystic luminal ameloblastoma in a young patient can be managed more conservatively — the histological subtype changes the plan.

§Viva questions

§MCQs

§Related diseases

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