Thyroid Nodules Flashcards
What is a thyroid nodule?
A thyroid nodule is a lump in the thyroid gland and is technically considered a goiter, often identified during routine exams or incidentally through imaging.
What percentage of thyroid nodules are cancerous?
Only about 5% of thyroid nodules are cancerous; the vast majority (95%) are benign.
What are some risk factors for thyroid cancer in a patient with a nodule?
Young age (children/young adults), history of neck/head radiation, and family history of thyroid cancer.
What are common benign causes of thyroid nodules?
Thyroid adenoma, toxic adenoma, toxic multinodular goiter, thyroid cysts, and Hashimoto’s thyroiditis.
What is the first investigation to order when evaluating a thyroid nodule?
Measure TSH (thyroid-stimulating hormone) levels and perform a thyroid ultrasound.
What features on ultrasound raise suspicion for malignancy in a thyroid nodule?
Hypoechoic solid nodules >1 cm, microcalcifications, central vascularity, rapid growth, and nodules taller than wide.
What is thyroid scintigraphy (thyroid scan)?
A nuclear medicine test where iodine or a similar tracer is used to assess thyroid nodule function, especially in low TSH settings.
What does a ‘hot’ nodule on thyroid scintigraphy indicate?
A functioning nodule that takes up iodine—usually benign and rarely cancerous.
What does a ‘cold’ nodule on thyroid scintigraphy indicate?
A non-functioning nodule that does not take up iodine—higher suspicion for malignancy and may require FNA.
What are the treatment options for a toxic adenoma identified on scintigraphy?
Surgery (thyroidectomy) or radioactive iodine therapy to ablate the overactive nodule.
What does a low TSH level typically indicate?
Low TSH usually suggests hyperthyroidism, often due to autonomous thyroid hormone production.
In a patient with a thyroid nodule and low TSH, what test should be ordered next?
A thyroid scintigraphy (radionuclide scan) should be done to assess the function of the nodule.
What type of nodule is suspected when a nodule takes up iodine on scintigraphy in the context of low TSH?
A ‘hot’ nodule (functioning), which is usually benign, commonly a toxic adenoma.
What type of nodule is suspected when a nodule does not take up iodine on scintigraphy in the context of low TSH?
A ‘cold’ nodule (non-functioning), which may be malignant and warrants further evaluation.
What is a likely diagnosis for a patient with a hot nodule, low TSH, and high T3/T4?
Toxic adenoma causing hyperthyroidism.
What is the management for a toxic adenoma?
Radioactive iodine therapy or surgical removal (thyroidectomy).
