Bone lesions in children are common yet difficult to manage, both for the concern that they arouse in the patient’s family and for their heterogeneous nature. Although most cases are benign, the distinction between benign and malignant bone tumours is not straightforward. A careful clinical and radiological evaluation is always necessary and sometimes helps to identify those lesions that in case of typical characteristics and unequivocal radiological evolution, absence of increased bone fragility and absence of associated general signs and symptoms (pain, fever) should only be monitored and do not require a more aggressive approach. Currently, these lesions are radiologically defined as “don’t touch lesions”. In the presented clinical case, close clinical and radiological follow-up led to the diagnosis of an aneurysmal bone cyst, therefore biopsy or surgical procedure stress to the patient and her family were avoided.