Florid reactive periostitis of the thumb

A case of florid reactive periostitis of the thumb is presented. This is a rare pseudosarcomatous lesion which generally has a benign radiographic appearance, but on histology it may be mistaken for a malignant process. The clinical behaviour may simulate a malignant tumour but after local excision there is very little propensity for recurrence. Local resection is the recommended treatment. Surgeons and pathologists should consider the possibility of florid reactive periostitis before making a diagnosis of sarcoma in the hand.