Pheochromocytoma is a special type of tumor originating from chromaffin cells of the adrenal gland. Most of these tumors are benign, with only a minority of patients experiencing malignancy. Clinically, the likelihood of tumor malignancy is about 10%. Most patients have a good prognosis after surgical removal, and if the tumor shows distant metastasis, it can be determined that the disease has become malignant. Due to the unique origin of pheochromocytomas in the adrenal medulla chromaffin cells, the tumor tissue continuously grows in the body and synthesizes and metabolizes catecholamines such as adrenaline, dopamine, and noradrenaline. Clinically, nearly 90% of patients do not develop cancer throughout their lives, therefore most pheochromocytomas are benign. However, about 10% of patients experience distant metastases, and once metastasized, it is considered a malignant tumor.