Thyroid nodules are very common. Studies suggest that 50-70% of people have a thyroid nodule. Over 90% of these are benign. Thyroid nodules can produce symptoms such as a lump that can be seen or felt in the neck, difficulty swallowing or breathing, a change to the voice or a feeling of a lump in the throat. Many thyroid nodules do not cause any symptoms.
Once a thyroid nodule is suspected it will be investigated with ultrasound and routine thyroid function blood tests. Fine needle aspirate ( FNA) biopsy will often be performed. FNA can return 6 different results, these are classified as follows:
Bethesda Classification of Thyroid FNA
| Classification | Result | Risk of Cancer | Management |
|---|---|---|---|
| I | Non diagnostic | 16% | Repeat FNA 6 months |
| II | Benign | 4% | Observe |
| III | Atypical / Follicular lesion of undetermined significance | 16% | Repeat FNA in 3 months |
| IV | Follicular neoplasm | 26% | Surgery |
| V | Suspicious for cancer | 75% | Surgery |
| VI | Malignant | 98% | Surgery |
If a nodule is benign on FNA and not causing any symptoms it can usually be observed with ultrasound every 6-12 months.
Surgery may be recommended in the following circumstances:
Nodule over 4cm as studies have shown FNA can be inaccurate in these circumstances
- Significant symptoms such as difficulty swallowing or breathing
- Nodules that are part of a multinodular goitre where the goitre is large or extending into the chest
- Nodules that are producing too much hormone
- Nodules that have a concerning appearance on ultrasound despite a benign FNA
- Nodules that are growing
Each circumstance is unique and your surgery will discuss a management plan with you.