A rare site for aneurysmal bone cyst - trapezium

Aneurysmal bone cyst (ABC) is a solitary, expansile and erosive lesion of bone. The cause of this non-neoplastic lesion is unknown. Most patients are under 20, but the tumor can occur at any age. The most common location is the metaphysis of the lower extremity long bones, more so than the upper extremity. But trapezium is a very rare location for this type of tumour and only few case reports have been published till date. Here we are reporting a 19 year old girl with aneurismal bone cyst of trapezium.