A 20-year-old woman presented with pain and swelling in her left thumb for 3 months. She had noticed a gradual enlargement of her left thumb for 3 months and did not seek medical attention until it became painful. She had no history of trauma or any systemic symptoms.

Physical examination of the left hand showed a localised swelling of variegated consistency over the left first metacarpal (fig 1). The overlying skin was normal and the movements of the metacarpophalangeal and trapeziometacarpal joints were painful and restricted. No neurovascular or cutaneous abnormalities were observed. The patient had pain in the clenched-fist position. No joint effusion was noticed. The laboratory investigations were unremarkable.

Radiographs of the left hand showed an expansile osteolytic lesion of the first metacarpal (fig 2). The margins of the lesion were well defined. The patient underwent fine-needle aspiration cytology (FNAC), which showed osteoclast-type multinucleate giant cells interspersed with stromal cells. The nuclei of stromal cells were morphologically similar to those of multinucleated giant cells, and mitotic figures were absent.

The treatment plan constituted local resection with reconstruction, considering the young age of the patient, intact phalanges and unwillingness for amputation. The tumour was resected with a cuff of surrounding normal tissue and protecting neurovascular bundle. An autograft of the tricortical iliac crest was taken to bridge the defect after resection of the tumour. K wires were used to fix the tricortical iliac crest graft placed between the trapezium and proximal phalanx. A thumb spica was applied to immobilise the thumb. Movement …