Adamantinoma

Definition

 

Rare low-grade malignant tumour

- cell of origin unknown

 

Epidemiology

 

Usually second or third decade of life

 

Site

 

90% diaphysis of tibia 

 

Mandible

 

X-ray

 

Most common anterior cortex of tibia

 

Soap-bubble appearance

 

Eccentrically located

- well circumscribed

- slightly expansile

- cortical thickening

- little or no periosteal reaction

- can have late deformity

 

DDx

 

Fibrous dyplasia

Osteofibrous dysplasia / Ossifying fibroma / Osteosarcoma

Giant cell tumour

ABC

Chondrosarcoma / CS

Infection / osteomyelitis

Unicameral bone cyst

 

Diaphyseal lesion / HALFEE

- Histiocytoma

- Adamantinoma

- leukemia

- FD

- EG

- Ewings

 

Pathology

 

Two distinctly different components

 

1.  Epithelial origin 

- composed of squamous cells and epithelial pearls 

 

2.  Mesenchymal origin 

- composed of immature mesenchymal cells and spicules of dysplastic bone

- closely resembles the pattern of fibrous dysplasia and its variant ossifying fibroma 

 

Adamantinoma is considered by some to be a malignant variant of fibrous dysplasia

- resemblance of the mesenchymal component to fibrous dysplasia / ossifying fibroma

- the presence of the epithelial component makes adamantinoma a distinctly different entity

 

NHx

 

Intra-osseous, intra-cortical Stage 1A Osteosarcoma

 

Metastasis in 20% of cases

 

Management

 

Wide excision

 

Biopsy followed by wide resection

- chemo and radiotherapy ineffective

- need to address bone loss

- vascularised fibular graft / allograft / bone transport

 

Results

 

Qureshi et al JBJS Am 2000

- multicentred retrospective review of 70 cases

- average age 31, more common in males

- limb salvage attempted in 91% and successful in 84%

- up to 50% complication rate with limb reconstruction (fracture, non union)

- wide operative margins associated with lower recurrence rates

- 87% 10 year survival