Osteoid Osteoma of the Distal Phalanx: A Rare Condition.

Osteoid osteoma of the distal phalanges in the hand is rare and difficult to diagnose. We report a case of a 37-year-old Caucasian female patient who presented with a mass on the distal phalanx of the index finger. The patient was suffering from intermittent nocturnal pain for more than 18 months along with thickening, localized swelling, and clubbing of the distal phalanx of the right index finger. Radiographs revealed a lytic lesion of the distal phalanx of the right index finger with surrounding sclerosis. An MRI showed an intramedullary lesion with infiltration of the bone marrow, cortex, and surrounding tissue with focal sclerosis and elements of enhancements. A presumptive diagnosis of osteoid osteoma was made and surgical removal of the lesion by curettage and bone grafting was the treatment of choice. The curetted specimen was sent to pathology and the diagnosis of osteoid osteoma was confirmed. The patient was asymptomatic at six months postoperatively. Osteoid osteoma should be included in every differential diagnosis for patients presenting with atypical features of the distal phalanx of the hand.