by Jason Wasserman MD PhD FRCPC
January 30, 2026
Follicular nodular disease is a benign (noncancerous) condition in which the thyroid gland contains one or more nodules. A nodule is a rounded area where thyroid cells have grown more than usual. The thyroid is a small, butterfly-shaped gland located at the front of the neck that helps control metabolism by producing thyroid hormones.
When many nodules are present, the condition is often called a multinodular goiter. Follicular nodular disease is very common, especially in adults, and most people with this condition never develop serious problems.
This article explains what follicular nodular disease means in a pathology report, how the diagnosis is made, what pathologists see under the microscope, and when further testing or follow-up may be recommended.
What are the symptoms of follicular nodular disease?
Most people with follicular nodular disease do not have symptoms. The nodules are often found during a routine physical exam or on imaging done for another reason.
When symptoms do occur, they are usually related to the size or number of nodules, not cancer. Symptoms may include a visible lump or swelling in the neck, a feeling of fullness or pressure, or difficulty swallowing or breathing if the thyroid is enlarged.
Less commonly, some people develop symptoms related to thyroid hormone imbalance, such as fatigue, weight changes, heart palpitations, or sensitivity to heat or cold. These symptoms depend on whether the thyroid is producing too much or too little hormone.
What causes follicular nodular disease?
The exact cause is not always known, but several factors can contribute. Iodine deficiency can lead to thyroid enlargement and nodule formation because iodine is needed to make thyroid hormone. Genetic factors also play a role, as thyroid nodules and goiter can run in families.
Long-standing thyroid inflammation, such as Hashimoto thyroiditis (an autoimmune condition in which the immune system attacks the thyroid), can also promote nodule development. In addition, prolonged stimulation of the thyroid by thyroid-stimulating hormone (TSH) may encourage nodular growth over time.
How is follicular nodular disease diagnosed?
The diagnosis is usually made using a combination of clinical evaluation, imaging, and sometimes tissue sampling.
Doctors often first detect nodules during a physical exam of the neck. A thyroid ultrasound is then used to assess the size, number, and appearance of the nodules. Ultrasound cannot diagnose cancer on its own, but it helps identify nodules that may need closer evaluation.
If a nodule has concerning features or is large, a fine-needle aspiration (FNA) biopsy may be performed. This involves using a thin needle to collect cells for microscopic examination. If part or all of the thyroid is removed surgically, a pathologist examines the tissue to confirm the diagnosis and to rule out cancer.
Microscopic features of follicular nodular disease
When examined under the microscope, follicular nodular disease shows a mixture of normal thyroid tissue and nodules formed by follicular cells (the cells that normally produce thyroid hormone). The nodules are usually well-defined but not encapsulated, unlike true tumors.
A common finding is hyperplastic follicles, meaning enlarged or irregularly shaped follicles. Colloid, a thick gel-like substance normally stored inside follicles, is often abundant.
Over time, nodules may show degenerative changes, which are signs of aging rather than cancer. These can include fibrosis (scar-like tissue), cyst formation (fluid-filled spaces), hemorrhage (bleeding), calcifications, and collections of immune cells that clean up old blood. These findings are common and expected in benign thyroid nodules.
What is the risk of cancer in follicular nodular disease?
Follicular nodular disease is a noncancerous condition. However, like any thyroid gland, a thyroid with follicular nodular disease can also develop cancer. If a cancerous tumour is identified, it will be described separately and clearly in the pathology report.
The overall risk of thyroid cancer is low, but it is not zero. For this reason, doctors pay special attention to nodules that grow quickly, feel firm or fixed, or have suspicious features on ultrasound.
A history of radiation exposure to the head or neck, especially during childhood, also increases concern. If any concerning features are present, additional testing, such as a repeat ultrasound, biopsy, or surgery, may be recommended.
What is the difference between follicular nodular disease and a goiter?
A goiter means that the thyroid gland is enlarged. Follicular nodular disease refers specifically to the presence of nodules. When an enlarged thyroid contains multiple nodules, the term multinodular goiter is often used.
What does it mean if a dominant adenomatoid nodule is present?
A dominant adenomatoid nodule is the largest nodule within the thyroid. Denomatoid nodules are benign, but they may receive closer attention because they are more likely to cause symptoms or raise concern on imaging. Your pathologist carefully examines the dominant nodule to ensure there are no features of cancer or precancerous change.
Questions to ask your doctor
- Do I have a single thyroid nodule or multiple nodules?
- Was there a dominant nodule?
- Are my thyroid hormone levels normal?
- Do I need treatment or just monitoring?
- How often should my thyroid be checked?
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