Differentiated thyroid cancer often has no symptoms in the early stages, with only incidental palpation of nodules of various sizes and textures on the front of the neck. Some patients may find abnormalities during routine physical examinations through imaging studies, and symptoms may appear only in the later stages. The second point concerns the characteristics of medullary thyroid cancer, which exhibits specific symptoms early on, such as persistent, watery diarrhea. Additionally, this cancer involves an endocrine syndrome, where tumor cells secrete calcitonin and adrenocorticotropic hormone, potentially leading to facial flushing, elevated blood pressure, and reduced blood calcium. This may be associated with other conditions such as pheochromocytoma, multiple mucosal neuromas, and parathyroid adenomas, which can also cause corresponding symptoms.