Approach to a thyroid nodule

Andy SherPGY-2 Family Medicine

Case

44 y.o. woman, 2 cm nodule palpable in left lobe of thyroid gland at annual exam – smooth, non-tender. No lymphadenopathy

No symptoms of hyper/hypo thyroid. No compressive symptoms

Past Med Hx: HTN Meds: HCTZ Fam Hx: no hx of thyroid disease

Epidemiology

Palpable thyroid nodules – 4-7% of population

Prevalence 19-67% - based on nodules found incidentally on ultrasound

4:1 women:men

Epidemiology

Geographic areas with iodine deficiency

Thyroid carcinoma in 5-10% of palpable nodules

Following ionizing radiation, nodules develop at a rate of 2% annually

Presentation

Majority are asymptomatic <1% cause hyperthyroidism Neck pressure or pain if spontaneous

hemorrhage

History

Symptoms of hyper or hypothyroidism Previous nodules, goiters, family

history of autoimmune thyroid disease, thyroid carcinoma, or familial polyposis

Hashimoto’s thyroiditis – association with thyroid lymphoma

History – Red Flags

Male < 20 years, > 65 years Rapid growth of nodule Symptoms of local invasion

(dysphagia, neck pain, hoarseness) Hx of radiation to head or neck Family hx of thyroid CA or polyposis

Physical Exam

Less than 1 cm usually not palpable ½ of all nodules detected by

ultrasonography not detected by physical exam

Should also examine for lymphadenopathy

Physical Exam

Smooth or nodular Diffuse or localized Soft or hard Mobile or fixed Painful or non-tender

Laboratory

TSH Serum calcitonin if family hx of

medullary thyroid carcinoma Do not use thyroid function tests to

differentiate benign from malignant

Radiology

Ultrasound to document size, location, and

character of nodule To determine changes in size of nodules

over time or to detect recurrent lesions U/S guided biopsy decreases the

incidence of indeterminate specimens

Radiology

Thyroid scan Can not reliably distinguish benign from

malignant nodules Cold nodules – 5-15% are malignant Hot nodules – almost always benign

Fine Needle Aspiration

Should be 1st test in the euthyroid patient Sensitivity 68-98% Specificity 72-100% False negative rate 1-11% False positive rate 1-8% Sampling errors in very large and very small

nodules – minimized by u/s guided biopsy

Treatment

Surgical treatment indications Malignancy Indeterminate cytology and suspicious

H&P Indeterminate cytology and “cold nodule” Toxic nodules (suppression of TSH,

symptoms – a-fib) – can use radioactive iodine or surgery

Repeated recurrence of cystic lesions

Treatment

Benign biopsies – can be followed without surgery and monitored q 6 months by physical exam, u/s

Surveillance – change in nodule size and symptoms – repeat FNA if nodule grows.

Suppression treatment

Post-operative suppression treatment following resection of cancer

TSH should be maintained for target of 0.5 mU per L

Greater suppression for high risk patients, metastatic or locally invasive not completely removed

Suppression treatment

For benign solitary nodule controversial

Follow at 6 month intervals Thyroxine to suppress TSH to 0.1 to

0.5 mU per L for 6-12 months After 12 months, maintain TSH in low

normal range

Incidental Nodule on U/S

Most are benign and can be monitored without further testing

FNA if nodule becomes palpable findings suggestive of malignancy on u/s larger than 1.5 cm Hx of head or neck irradiation Strong family hx of thyroid cancer

Case

44 y.o. woman, 2 cm nodule palpable in left lobe of thyroid gland at annual exam – smooth, non-tender. No lymphadenopathy

TSH ordered – normal Thyroid u/s – confirms 2 cm nodule,

solid FNA - benign

Case

Repeat U/S at 1 year – nodule now 2.5 cm in size

Repeat FNA – benign Could consider suppression therapy,

or continue to follow.