RET and metastatic neoplasm: Previous findings demonstrate osteoclast-induced bone destruction plays a role in bone cancer pain.27 The tumour can also invade or compress nearby peripheral nerves, causing pain through direct nerve involvement.28 In cases of metastatic disease, especially when the tumour spreads to internal organs (eg, lungs), visceral pain may also develop.29 Further research is required to determine the precise mechanism of action related to neuropathic pain, such as rearrangement during transfection (RET) tyrosine kinase receptor signalling pathway.30,31