Detailed answer

While hyperpigmentation, which is the darkening of an area of skin or nails, can occur in some cases of thyroid dysfunction, it is not a common symptom of thyroid cancer specifically. Hyperpigmentation is more commonly seen in conditions such as Addison's disease or certain medications. If you are concerned about thyroid cancer or experiencing any other symptoms, it is important to consult with a medical professional for proper evaluation and diagnosis.