Langerhans Cell Histiocytosis With Secondary Aneurysmal Bone Cyst in a 9-Year-Old Boy’s Femur: A Case Report

ABSTRACT

Secondary aneurysmal bone cysts (ABCs) associated with Langerhans cell histiocytosis are rare. Although cases of ABCs arising from Langerhans cell histiocytosis in the skull have been reported in several studies, to the best of our knowledge, only two femur cases have been reported. In this case study, we described a 9-year-old boy with Langerhans cell histiocytosis of the femur. Magnetic resonance findings indicated internal multilocular cysts and multiple fluid–fluid levels, which are typical of ABCs. ABCs rarely occur in conjunction with Langerhans cell histiocytosis. Our findings may be helpful in the differential radiological diagnosis of pediatric bone tumors.