Aneurysmal bone cysts are benign active or aggressive bone tumors that commonly arise in the long bones, especially the femur,
tibia, and humerus and the posterior elements of the spine. Aneurysmal bone cysts affect all age groups but are more common
before skeletal maturity (first two decades of life). They usually involve the metaphysis or metadiaphyseal region of long
bones. Although juxtaphyseal lesions abutting the growth plate and extending into the epiphysis have been described, there
is no report of an aneurysmal bone cyst entirely and primarily located in the epiphysis. We report on a 3-year-old boy who
presented with an entirely contained aneurysmal bone cyst to the proximal tibial epiphysis. We discuss the clinical presentation,
diagnosis, including imaging and pathology, and treatment. A review of the pertinent literature also is presented.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has approved the reporting of this case report, that all investigations
were conducted in conformity with ethical principles of research, and that informed consent for participation in the study
was obtained.
This work was performed at The Children’s Hospital of Philadelphia.