BONE PATHOLOGY CASE STUDIES

CASE 6 - Aneurysmal bone cyst

Clinical History:

This 18 year old female presents with pain and swelling of her right distal thigh associated with activity. She is a cheerleader and notices tenderness after performing acrobatics. She has no history of any trauma. Radiographs show an expansile, eccentric lesion located in the metaphysis of the distal femur that is surrounded by a rim of reactive new bone as a host response. (Slide 6.1)
  1. What is the diagnosis?

    This is an aneurysmal bone cyst (ABC).

  2. What is the major differential diagnosis?

    3. This is an aneurysmal bone cyst. and the major differential is giant cell tumor of bone (which occurs in the epiphysis, is more cellular, does not have periosteal reaction, occurs more in adults, and has a tendency to recur after resection).

  3. In whom and at what sites is this lesion most common?

    4. ABC's have a female predominance and occur in children to young adults. Vertebra, femur, and tibia are most often affected.

  4. Why should these lesions not be treated with radiation?

    5. There is a tendency for these lesions to undergo malignant transformation when radiated.