Merck Manual

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Approach to the Patient With a Thyroid Nodule


Jerome M. Hershman

, MD, MS, David Geffen School of Medicine at UCLA

Last full review/revision Sep 2020| Content last modified Sep 2020
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Thyroid nodules are benign or malignant growths within the thyroid gland. They are common, increasingly so with increasing age.

The reported incidence varies with the method of assessment. In middle-aged and older patients, palpation reveals nodules in about 5%. Results of ultrasonography and autopsy studies suggest that nodules are present in about 50% of older adults. Many nodules are found incidentally on thyroid imaging studies done for other disorders.


Evaluation of a Thyroid Nodule


Pain suggests thyroiditis or hemorrhage into a cyst. An asymptomatic nodule may be malignant but is usually benign. Symptoms of hyperthyroidism suggest a hyperfunctioning adenoma or thyroiditis, whereas symptoms of hypothyroidism suggest Hashimoto thyroiditis Hashimoto Thyroiditis Hashimoto thyroiditis is chronic autoimmune inflammation of the thyroid with lymphocytic infiltration. Findings include painless thyroid enlargement and symptoms of hypothyroidism. Diagnosis... read more . Risk factors for thyroid cancer include

Physical examination

Signs that suggest thyroid cancer include stony, hard consistency or fixation to surrounding structures, cervical lymphadenopathy, and hoarseness due to recurrent laryngeal nerve paralysis.


  • Thyroid-stimulating hormone (TSH)

  • Antithyroid peroxidase antibodies

If thyroid-stimulating hormone (TSH) is suppressed, radioiodine scanning is done. Nodules with increased radionuclide uptake (hot) are seldom malignant. If thyroid function tests do not indicate hyperthyroidism Hyperthyroidism Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of free thyroid hormones. Symptoms are many and include tachycardia, fatigue, weight loss, nervousness, and tremor... read more Hyperthyroidism or Hashimoto thyroiditis, fine-needle aspiration biopsy done under ultrasound guidance is done to distinguish benign from malignant nodules. Early use of fine-needle aspiration biopsy is a more economic approach than routine use of radioiodine scans.

Ultrasonography is useful in determining the size of the nodule; fine-needle aspiration biopsy is not routinely indicated for nodules < 1 cm on ultrasonography or for nodules that are entirely cystic. Ultrasonography is rarely diagnostic of cancer, although cancer is suggested by certain ultrasonographic or x-ray findings:

Treatment of a Thyroid Nodule

  • Treatment of underlying disorder

Treatment is directed at the underlying disorder. Thyroxine suppression of TSH to shrink smaller benign nodules is effective in no more than half the cases and is seldom done. Thyroxine is not used to treat cancerous nodules.

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