Thyroid nodules are common growths or lumps that form within the thyroid gland, a butterfly-shaped organ located at the base of the neck. When multiple growths develop, the condition is referred to as multiple thyroid nodules or multinodular goiter. This condition is prevalent, particularly among older individuals and women, with over half of women aged 50 or more potentially having detectable thyroid nodules. Understanding their nature and management approaches is important.
Understanding Thyroid Nodules
Thyroid nodules are an overgrowth of cells within the thyroid gland, which can be solid or fluid-filled. The development of multiple nodules, or a multinodular goiter, often occurs over many years, contributing to its increased prevalence with age. These nodules vary in size and composition, and their presence can lead to an irregular appearance of the thyroid gland.
Distinguishing between benign (non-cancerous) and malignant (cancerous) growths is a primary concern. Most thyroid nodules (over 90%) are benign. However, a small percentage (4% to 6.5%) can be cancerous. While many nodules cause no noticeable symptoms, especially when small, larger or more numerous nodules can sometimes lead to discomfort. If nodules grow significantly, they might cause difficulty swallowing, breathing difficulties due to pressure on the windpipe, or voice changes like hoarseness.
Detection and Evaluation
Multiple thyroid nodules are frequently discovered incidentally during imaging tests for unrelated conditions, or during a routine physical neck examination. A physical examination allows a healthcare professional to palpate the neck for lumps or enlargement.
Initial diagnostic steps include blood tests, such as thyroid function tests measuring thyroid-stimulating hormone (TSH) levels, to assess gland function. Ultrasound is the primary imaging tool for evaluating thyroid nodules. This technique provides detailed visualization, determining their number, size, and characteristics (solid, cystic, or calcifications). These ultrasound characteristics help assess malignancy likelihood.
If ultrasound findings suggest a suspicious nodule, or if a nodule is of a certain size, a Fine Needle Aspiration (FNA) biopsy may be recommended. This procedure uses a thin needle to collect cells directly from the nodule. The collected cells are then examined under a microscope to determine if the nodule is benign or malignant. While FNA is effective for identifying malignancy, about 22% to 27% of specimens may yield indeterminate or suspicious results, sometimes requiring further evaluation.
Management Approaches
Once multiple thyroid nodules have been evaluated, the management approach is tailored to the individual, considering nodule characteristics, symptoms, and patient preferences. For benign, asymptomatic nodules, observation or active surveillance is a common strategy. This involves regular follow-up appointments, often including repeat thyroid ultrasounds to monitor for changes in nodule size or characteristics, and periodic blood tests to check thyroid function.
Medical management might be considered in some cases, though it is less common for benign nodules without functional issues. For instance, if nodules cause the thyroid to produce excessive hormones, leading to hyperthyroidism, medication might be used to regulate hormone levels. However, routine thyroid hormone suppression therapy for benign nodules is often debated.
Minimally invasive procedures offer an alternative for select benign nodules causing symptoms, such as significant size or cosmetic concerns. Radiofrequency ablation (RFA) or ethanol ablation are examples. RFA uses heat to reduce nodule size, while ethanol ablation involves injecting alcohol into cystic nodules to shrink them. These methods aim to alleviate symptoms without traditional surgery.
Surgical removal, known as thyroidectomy, is generally recommended for confirmed malignant nodules, those highly suspicious for cancer based on biopsy results, or very large benign nodules causing compressive symptoms like difficulty breathing or swallowing. Surgery might also be considered for cosmetic reasons if a large nodule is visibly prominent. Depending on the situation, a partial thyroidectomy (removal of part of the gland) or a total thyroidectomy (removal of the entire gland) may be performed. The decision for surgery and its extent is made based on the specific type and spread of any malignancy, or the severity of symptoms caused by benign nodules.