Thyroid Nodules Hollis Moye Ray, MD SEAHEC Internal Medicine June 3, 2011

Thyroid Nodules Palpable: 4 – 7% Detected on ultrasound: 20 – 65% More common: aging, women Cancer risk: 5 – 10%

Benign Causes Multinodular (sporadic) goiter ("colloid adenoma") Hashimoto's (chronic lymphocytic) thyroiditis Cysts: colloid, simple, or hemorrhagic Follicular adenomas Macrofollicular adenomas Microfollicular or cellular adenomas Hurthle-cell (oxyphil-cell) adenomas Macro- or microfollicular patterns

Malignant Causes Papillary carcinoma Follicular carcinoma Minimally or widely invasive Oxyphilic (Hurthle-cell) type Medullary carcinoma Anaplastic carcinoma Primary thyroid lymphoma Metastatic carcinoma (Breast, renal cell, others)

Thyroid Cancer Lower prevalence in “Hot nodules” Multinodular goiters Higher prevalence in Male Children Adults 60 years old History of head/neck irradiation Family history of thyroid cancer Rapid growth Hoarseness

Evaluation History Rapid growth? Family history? Irradiation? Cancer syndromes? Physical Examination Fixed, hard mass Vocal cord paralysis Cervical lymphadenopathy Obstructive symptoms

Evaluation TSH Low  Thyroid scintigraphy Not low  US to select for FNA biopsy; evaluate for hypothyroidism Ultrasound High risk of cancer: hypoechoic, microcalcifications, increased central vascularity, irregular margins, taller than wide, documented enlargement, size >3cm Low risk of cancer: hyperechoic, peripheral vascularity, pure cyst, comet-tail shadowing

Evaluation Thyroid Scintigraphy Select nodules for FNA Uses radioisotope to detect “hot” and “cold” Most benign and virtually all malignant thyroid nodules are “cold” (take up less/no isotope) Helps to guide FNA biopsy

Evaluation FNA biopsy Procedure of choice Safe and simple 90 – 95% of sensitive False negative rate only 1 – 11% What to biopsy? Basically all >1cm EXCEPT Spongiform nodules < 2cm Purely cystic nodules

Other Lab Tests Calcitonin Controversial – consider if hypercalcemic, family history, or MEN type 2s Anti-TPO Antibodies Only recommended if suspicious for autoimmune disease (i.e. Hashimoto’s) Thyroglobulin Does not discriminate benign from malignant Can be useful s/p thyroidectomy or ablation

Diagnostic Categories Benign —macrofollicular or adenomatoid/hyperplastic nodules, colloid adenomas, nodular goiter, and Hashimoto's thyroiditis. Follicular lesion of undetermined significance — lesions with atypical cells, or mixed macro- and microfollicular nodules. Follicular neoplasm —microfollicular nodules (i.e. Hurthle cell lesions) Suspicious for malignancy Malignant Nondiagnostic

Management

Benign Nodules Macrofollicular or adenomatoid/hyperplastic nodules, colloid adenomas, nodular goiter, and Hashimoto's thyroiditis Followed without surgery T4 therapy (?) – MAY decrease size, prevent further growth Periodic ultrasound monitoring Repeat aspiration if change in size, texture, or new symptoms

Follicular lesion of undetermined significance Nodules with atypical cells, nodules w/ both macro and microfollicular features Risk of malignancy: 5-10% Excision: no definite consensus ? Follow with aspiration - if atypical cells found, then excise

Follicular neoplasm (microfollicular) If TSH normal – typically surgery If TSH low - perform thyroid scintigraphy If hyperthyroid – radioiodine tx or surgery Hyperfunctioning (autonomous) – followed Non-autonomous – surgery w/path eval for vascular or capsular invasion 15 – 25% cancerous

Malignancy = Surgery* Papillary and Follicular - well-differentiated and good prognosis if in early stage Medullary Anaplastic – poorly differentiated and aggressive Metastatic Suspicious for malignancy – surgery 50 – 75% malignant *Thyroid lymphoma – the exception Radiation, not surgery!

Management of other path findings Nondiagnostic FNA – repeat under US Cystic thyroid nodules – followed or excised for therapeutic reasons if recurrent Ablation – benign, autonomous, or cystic Inject ethanol or other sclerosing agent Controversial (complications, prolonged pain)

References MKSAP 15: Endocrinology and Metabolism Harrison’s Internal Medicine UpToDate: Thyroid Nodules

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