1. Adamantinoma Ted Scriven Sept 15 th, 2008

2. Adamantinoma is a malignant bone tumour Definition

3. Rare < 1% of primary bone tumours Patents mostly 2 nd and 3 rd decade of life, but wide range overall Predilection for tibia - ~ 80% of cases Usually occurs in diaphysis Slight male predominance  1.25:1 Epidemiology

4. Theory: –Adamantinoma arises from aberrant nests of epithelial cells – this would explain why the high occurrence in the subcutaneous proximal tibia Theory: –Osteofibrous dysplasia is benign precursor to adamantinoma –? 2 types – classic (>20yo) and differentiated (<20yo – transformed from OFD) Etiology

5. Slow growing  therefore symptoms may be present for years Most common symptom: Pain Occasionally palpable mass (due to subcutaneous location) 20% present with pathologic fracture Clinical

6. Xray: –Geographic –Lucent –Eccentric –Usually, multiple lesions separated by areas of sclerosis –“soap bubbles” –Cortical thinning –No periosteal reaction –Usually, no soft tissue mass Radiological

7. CT –Not as useful as MRI MRI –T1: low signal intensity –T2: high signal intensity Radiological

8. osteofibrous dysplasia fibrous dysplasia ABC chondromyxoid fibroma chondrosarcoma DDx

9. Gross: –Lobulated –Rubbery –May have focal areas of hemorrhage and necrosis –May have bone spicules and cysts filled with blood Pathology

10. Microscopic: –“Islands” or “nests” of epithelioid cells in a fibrous stoma –May resemble fibrous dysplasia or osteofibrous dysplasia –Minimal nuclear atypia, rare mitotic figures –Immunohistochemical staining: + for cytokeratins and vimentin Pathology

11. Wide resection or amputation Radio-resistant Chemo not shown to be effective Treatment

12. Prognosis depends on surgical margins Recurrence in 25 - 32% who do not undergo wide resection or amputation (< 10% by wide excision) Mets occur in up to 30% Mets usually in lungs or lymph nodes 85% survival at 10 yrs? Long term follow up very important as tumour is slow-growing Prognosis

13. THANK YOU