Adamantinoma
Synonyms: Adamantinoma of long bones
Rare primary bone malignancy with uncertain histogenesis
Quick Facts
Behaviour
Malignant
Category
Bone
Grade
Variable
Synonyms
Adamantinoma of long bones
Category
Bone
Behaviour
Malignant
Grade
Variable
Gender
Male
Tissue of Origin
Epithelial (unknown origin)
Epidemiology
- Rare, <1% of primary bone tumours
- Wide age range with peak incidence in 2nd–4th decades
- Ranges from OFD-like adamantinoma, classic adamantinoma and dedifferentiated adamantinoma
Clinical Features
- Slowly progressive pain and swelling over years
- Palpable anterior tibial mass in most cases
- Rare pathological fracture
- Slow-growing but malignant course
Location
- Tibia in 90% of cases (anterior cortex)
- Fibula in 10%
- Rarely other long bones or axial skeleton
Imaging
- Plain radiograph: eccentric cortical lytic lesion with soap-bubble appearance and anterior tibial bowing . Multifocal lesions can be present in same bone
- MRI: lobulated low-signal mass
Pathology
- Biphasic tumour: epithelial nests in fibrous stroma
- Four histological subtypes: basaloid, tubular, spindle cell, squamoid
- Keratin-positive epithelial component
- Associated osteoFibrous dysplasia in periphery
Genetics
Positive for vimentin, keratin, p63
Treatment
- Wide local excision with adequate margins
- Limb salvage feasible in most cases
- Amputation for extensive local disease
- Fibular reconstruction may be required
Prognosis
- Metastasis in 12-30% (lungs, lymph nodes)
- Late recurrence and metastasis possible (>10 years)
- Juvenile form (OFD-like) has better prognosis with recurrence of 20%
Key Points
- Rare primary bone malignancy with uncertain histogenesis
- Tibial predilection is virtually diagnostic
- Characterized by epithelial structures embedded in an osteofibrous dysplasia-like stroma
- Osteofibrous dysplasia-like variant may precede or coexist with classic form
Workup - Blood Tests
- FBC, U&E, LFTs - preoperative baseline
- Bone profile - alkaline phosphatase
- Coagulation screen
Workup - Local Imaging
- Plain radiograph
- MRI with contrast of whole bone
Workup - Biopsy
- Core needle biopsy at sarcoma centre
- Immunohistochemistry: cytokeratin (AE1/AE3, MNF116) positive - confirms epithelial component
- EMA, p63 positive; S100 negative
- Exclude metastatic carcinoma: clinical and radiological correlation essential
Workup - Staging
- CT chest for pulmonary and lymph node staging
- Whole-body imaging if metastatic disease suspected
Workup - Other
MDT review with sarcoma specialist centre
Follow-up Summary
Grade 2–3 Chondrosarcoma, Periosteal and Parosteal Osteosarcoma - Post Resection
Discharge at 10 years - late recurrence and metastasis possible beyond 10 years; advise self-monitoring
Medical disclaimer
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