A 16-year-old girl from Mumbai undergoes MRI of the right proximal humerus for shoulder pain. Imaging shows a well-circumscribed, homogeneous lesion with low T1 and low T2 signal intensity, located in the metaphysis with a sclerotic rim on radiographs. No soft tissue mass or cortical breakthrough is seen. The lesion measures 2 cm. What is the most appropriate next step in management?