Massive Post-traumatic Femoral Cyst Resulting in Pathologic Fracture in a Child: A Case Report.

Case: A 10-year-old boy experienced a pathologic diaphyseal femur fracture through a large cyst encompassing 40% of femoral length. At age 5, he had had a traumatic ipsilateral diaphyseal femur fracture, treated with flexible nailing. Biopsy at age 10 revealed a simple bone cyst with components of aneurysmal bone cyst.