2.1
Thyroid nodules may be cystic, colloid, hyperplastic, adenomatous or cancerous. The majority of thyroid nodules are benign and they are often asymptomatic. There may be a single thyroid nodule (solitary nodule) or multiple thyroid nodules (multinodular goitre). Thyroid nodules can cause an overactive thyroid, which affects the normal production of thyroxine or triiodothyronine.