THYROID TUMOUR

any of various benign tumours (adenomas) or cancerous tumours of the thyroid gland. Most thyroid tumours are adenomas; these have a wide variation of cellular patterns, usually having well-developed follicles; thus, they are collectively known as follicular adenomas. Cancerous thyroid tumours are relatively rareonly about 0.5 percent of all cancer deaths are from this cause. Peak incidence occurs at about age 50 and affects women twice as frequently as men. It is speculated that both large doses of radiation to the neck area and prolonged hypersecretions of thyroid-stimulating hormone from the anterior pituitary predispose to thyroid cancer.