Introduction: A benign bone tumour arising from undifferentiated connective tissue cells of bone marrow. Occurs in the mature skeleton usually around knee and at wrist. It is an aggressive tumour and the chances of recurrence following curettage are very high. A small percentage might even metastasise to lungs.

Incidence: much more common in India, especially South India (4 to 6 times), than the western world.

Differential Diagnosis: Aneurysmal bone cyst, Benign Fibrous histiocytoma and aggressive chondromyxoid fibroma, Hyperparathyroidism

Prevention: Nil

Investigations: Plain x-ray, CT scan, MRI, wide bore needle biopsy

Treatment: Curettage with high speed burr, curettage with usage of adjuvants like phenol or liquid nitrogen (cryosurgery) have been in usage. However, extended curettage has the least chances of recurrence. Excision in toto is ideal if the bone involved is expendable (like lower ulna, proximal fibula). In instances like lower radius, excision and reconstruction using proximal fibula is practiced. In weight bearing bones like distal femur or proximal tibia, when the bone is totally destroyed, resection arthrodesis (Enneking procedure) is ideal if the patient

belongslowersocioeconomicgroup.Butifthepatientbelongstohigherstrata wheretheloaddemandsareless,excisionandcustommegaprosthesismaybe practiced. In fungating cases or after repeated recurrences, an amputation may be the last resort.