Is a lump or nodule on a thyroid usually cancerous?

Not necessarily: Thyroid nodules may be benign or malignant (cancerous). Statistically speaking, they are more likely to be benign. However, biopsy or excision may be necessary to make this distinction with certainty. Discussion with your doctor is recommended.

It is usually benign: No. The risk for a thyroid nodule to be canerous actually is only 5-6%- majority is benign. If you have a nodule on the thyroid, you should follow up with your doctor and serial ultrasound for thyroid nodule perhaps is necessary to be done, and biopsy can be done if thyroid nodule looks suspicious. Discuss with your doctor in detail.

Thyroid nodule: No. They are usually benign. However, ultrasounds can be done to look at the thyroid better and a fine needle aspiration can be attempted to get a diagnosis of the mass if your doctor is suspicious. If you have a mass, please see a doctor to get worked up properly.