A Case of Aneurysmal Bone Cyst of Fourth Metacarpal Bone: A Rare Entity at Unusual Location

Abstract

An Aneurysmal Bone Cyst (ABC) is a locally aggressive, rapidly growing, rare benign bone tumour that typically occurs in children and early adulthood. It usually occurs in the first and second decades of life, with a female predominance. The long bones of the lower extremities and spine are common sites for ABC, with rare involvement of the small bones of the hand. An 18-year-old female presented to the hospital with progressive swelling over her left hand for 4 to 5 months, associated with pain. Local examination elicits pain and tenderness over the 4th metacarpal bone with restricted movement at the Metacarpophalangeal (MCP) joint. A histopathological diagnosis of ABC was made due to the presence of osteoclastic giant cells lining a cyst, along with areas showing a pool of haemorrhage and stromal cells. The postoperative period remained uneventful, with no complaints of pain and good healing of the operation site noted during follow-up. Metacarpal bones are rare sites for ABCs.

Keywords

• bone tumours
• giant cell lesion
• metacarpophalangeal