Journal of Research in Medical Sciences1735-199517120120114Unicameral bone cyst of the proximal tibia in a five year old girl80388038ENMohammad AliTahririanAssistant Professor, Department of Orthopedic Surgery, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. tahririan@med.mui.ac.irMehdiMotififard2012011220120112Unicameral bone cysts (UBCs) are benign, osteolytic lesions which are often asymptomatic and are commonly seen in the proximal of humerus and femur. The average age at diagnosis is 9-11 years and there is a male preponderance with a male-to-female ratio of approximately 2-2.5 to 1. We describe a case of 5-year-old girl who presented to orthopedic clinic with a 4-month history of painful limping. Plain radiography of the right knee demonstrated a well-defined lytic lesion in the proximal of the tibia. Open biopsy and then curettage and bone grafting with bone- substitute was performed. The diagnosis of this condition requires a high index of suspicion. This report demonstrates that all UBCs do not have the same clinical patterns and with adequate attention good results can be achieved.KEYWORDS: Unicameral Bone Cyst, Benign, Limping, Pain