Abstract
INTRODUCTION: Aneurysmal bone cyst (ABC) is a rare, benign, cystic, hemorrhagic expansile osteolytic lesion of unknown etiology resembling multiple intraosseous blood-filled spaces mostly seen in the first two decades of life. It accounts for <1% of all bone tumors and the usual sites are the metaphyses of the proximal and distal femur, proximal tibia, and posterior elements of the spine. Affection of other sites is unusual. CASE REPORT: A 55-year-old female with a 5-month history of pain and swelling of distal ulna. She was operated on with curettage, bone grafting, and plating. At 1-year follow-up, she regained complete movements without any recurrence. CONCLUSION: In this article, we present a case of a primary ABC of distal ulna in an unusual age group of 55 years in a female. The clinical presentation, diagnosis, surgical management, and clinical outcome at 1 year are described.