What is a Thyroid nodule?

A thyroid nodule is a lump in an otherwise normal thyroid gland. Thyroid nodules are very common and it has been estimated that clinically one in every 12-15 women and one in every 40-50 men have a thyroid nodule.When patients who are asymptomatic are investigated by high definition ultrasounography 50-70% have thyroid nodules.Less than 5% of these nodules are malignant and many are cysts. The most common types of benign thyroid nodules are adenomas (benign overgrowths of normal thyroid tissue), cysts and Hashimoto's Thyroiditis. Uncommon types of benign thyroid nodules are due to subacute thyroiditis, silent thyroiditis or Reidel's thyroiditis. Papillary carcinoma accounts for almost 60% of malignant nodules and follicular carcinoma  15%. These malignant carcinomas are well differentiated and have a good prognosis.Patients with thyroid nodules  should be referred urgently to a physician with a special interest in thyroid disease if  the thyroid lump is associated with voice change,rapid enlargement, cervical lymphanopathy or persistent pain The UK guidelines expect such a patient to be seen by a specialist within two weeks of seeing their primary physcian.Any patient with stridor (noisy breathing) and a thyroid lump should be seen by a specialist the same day. Solitary solid thyroid masses are very rare in children, when they do occur 80% are malignant and 80% on presentation will have lymph involvement with cancer. So often children with solitary thyroid nodules are neglected mainly because of ignorance by their doctors. Fortunately when treated even though the tumour has spread the prognosis is exellent.

The British Medical Journal in 2009 contains an exellent article on the investigation of thyroid nodules. This article is aimed at physicians but is quite suitable for the general public. The reference is :

Investigating the thyroid nodule. HM Mehanna,AJ Kain,RP Morton J Watkinson, A Shaha BMJ 2009 338 705-709