Osteochondromas are benign bony lesions that have associated cartilaginous caps.

It has the potential for malignant transformation. Any growth after skeletal maturity, new-onset non-traumatic pain, fracture, lytic lesions or cortical irregularity warn investigation with MRI to rule out malignant transformation. 

In this case, its size is increasing before skeletal maturity without any other sign of malignant transformation, so no further MRI imaging is needed.