Diaphyseal desmoplastic fibroma of humerus--report of a rare presentation.

Desmoplastic fibroma is a rare locally aggressive benign tumour. It is most frequently reported in mandible, metaphysis and metadiaphysis of long bones. This tumour has been observed infrequently in the diaphysis like the one presented here. An 18-year-old female presented with progressive swelling left arm and dull aching pain for 1 year. She had a bony hard lobular well-defined swelling in the midshaft of humerus, which was not warm but tender. There was abnormal mobility present indicating a fracture. Plain radiograph of the affected arm showed an expansile, well-defined, intraosseous, radiolucent lesion with expansion involving the entire circumference of the humerus. An open biopsy was carried out and the report came out to be desmoplastic fibroma. She underwent wide segmental resection and interlocking nailing and bone grafting. After 6 weeks follow-up, the patient had visible callus and by 12 weeks there was significant union.