Thyroid Nodules

March 19, 2003

Objectives

? Identify patients at risk for thyroid cancer? Understand general approach toward

laboratory and radiologic evaluation of solitary thyroid nodules

? Familiarity with treatment modalities to facilitate appropriate follow up and referral

Case presentations:JM 26 y/o Latino male patient c/o increased unilateral neck

swelling for approximately one year. He thinks it may have been present since he was a teenager. Per his chart he was referred to ENT about 1 year ago, in which they note a right neck swelling and recommend f/u in 3mo if persistence or enlargement. Currently the mass is firm, fixed and about 1.5cm over the right lateral neck. There are no remaining masses over his neck, but the in the right lobe of his thyroid you note a similar 1cm firm, nontendernodule.

Case presentationsMK 53 y/o Ukrainian male presenting with 6 month

history of unilateral nontender neck swelling. Notes at onset rapid growth, now stable. Denies other neck swellings. On exam, 3cm rubbery,slightly mobile, nontender nodule on left lateral lobe of thyroid

History

Medical history:- personal history of thyroid disease- signs or symptoms of hyper/hypo thyroidism- symptoms of local invasion: hoarseness, dysphagia, neck pain- history of onset and rate of growth of nodule- history of radiation to head or neck

History

Family history:

- family history of thyroid ca or polyposis(Gardner’s syndrome) or autoimmune thyroiditis(Hashimoto’s)

History of Radiation ExposureGreatest risk of thyroid ca: exposure in childhood? Hodgkins lymphoma – with radiation treatment? US born- 1940’s/50’s frequent use of radiation to treat

nonmalignant conditions (ie: chronic cystic acne)- often medical records unavailable- ask if mother had to leave room during tx,

contradictory hx is memory of purple light (UV tx)- low risk if radiation tipped rods placed through

nose to post. pharynx to shrink tonsils/adenoids of children

History of Radiation Exposure? Foreign born-

-1986 Chernobyl, atomic bombing in Nagasaki/Hiroshima, Marshall Islanders exposed to nuclear testing

-map of Chernobyl: www.greenfield.fortunecity.com/flytrap/250/31.jpg

Physical ExamInspectionPalpation:

thyroid- note if nodules are: solid or cystic , smooth or nodulardiffuse or localizedsoft or hardmobile or fixedpainful or nontender

note size and location

if nodule is less than 1 cm often difficult to palpate on exam

Physical Exam cont.Palpation-

Lymph nodes- crucial to check for lymphadenopathy

Physical exam for any signs of hyper or hypothyroid disease, such as exothalpmos, reflex abnormalities, myxedema

“Red Flags” for thyroid cancer? Male gender? Extremes in Age (<20 y/o or >65 y/o)? Rapid growth of nodule? Symptoms of local invasion (dysphagia,

hoarseness, neck pain)? History of radiation to head or neck? Family hx of thyroid cancer or polyposis

(Gardner’s)

Back to the patients…JM: 26 y/o male Medical hx:no symptoms of thyroid dysfxnno personal hx of thyroid diseaseno known exposure to radiationno symptoms of local invasionFamily hx:nonePE:Firm fixed nodule with LADnl reflexes, no signs of thyroid disease

Back to the patients…MK: 53 y/o male Medical hx:no symptoms of thyroid dysfxnno personal hx of thyroid disease+ known exposure to Chernobyl at age 36no symptoms of local invasionFamily hx:nonePE:Cystic soft mass, no LADnl reflexes, no signs of thyroid disease

Epidemiology of Thyroid Nodules:

Palpable nodules- 4-7% of population- one study with 30% incidental nodule on US- 23% of solitary nodules are dominant in multinodular goiter- women 4x> men, more often in areas of iodine deficiency- thyroid ca in 5-10% of palpable nodules

Types of thyroid nodulesAdenoma:Macrofollicular adenoma (colloid)Microfollicular adenoma (fetal)Embyronal adenoma (trabecular)Hurthle cell adenoma (oxyphilic, oncocytic)Atypical adenomaAdenoma with papillaeSignet-ring adenoma

Cyst:Simple cystCystic/solid tumors (hemorrhagic, necrotic)

Carcinoma:Papillary (75%)Follicular (10%)Medullary (5-10%)Anaplastic (5%)Other: thyroid lymphoma (5%)

Colloid NoduleDominant nodule in multinodule goiter

Other:Inflammatory disorders (subacute or

chronic lymphocytic thyroiditis, granulomatous disease)

Developmental- dermoid, unilateral lobe agenesis

DiagnosisLaboratory Evaluation

Fine Needle Aspiration

RadiologyUltrasoundNuclear Imaging

Laboratory EvaluationSensitive TSH – all patients to differentiate hypo vs

hyperthyroid- important in determining next step of

workup- not useful in determining malignant from

benign nodule

Serum calcitonin – measure in patients with family hx of medullary thyroid ca

Antithyroid peroxidase antibodies and thyroglobulin-not to differentiate malignant from benign. helpful in diagnosing Grave’s or Hasimoto’s

Fine-Needle Aspiration? Euthyroid patient – first step ? Most cost effective in determining malignant vs. benign? Most accurate (~95% depending on biopsy skill and

cytopathologist skill)? Sensitivity 68-98%, specificity 72-100%, false (– ) 0-5%? Sampling error in large (>4cm) and small (<1cm) nodules? Results improved with US guided FNA, not routinely

used due to costs

Fine Needle Aspiration? Results:

benign- macrofollicular or “colloid” adenomas, Hashimoto’s – 74%

suspicious or indeterminant/inadequate –microfollicular or cellular adenoma (follicular neoplasm)22%

malignant - 4%

Thyroid Scintigraphy? Cannot reliably distinguish malignant vs. benign

? Measures the amount of iodine trapped within a nodule

? Nodule classified as :cold- decreased uptake

warm- uptake similar to surrounding tissue

hot- increased uptake (10%)

Thyroid Scintigraphy? Use with

1. suppressed TSH 2. indeterminate cytology

? Cold and warm- malignant 5-8%

? Hot nodule- almost always nonmalignant

? Indeterminate scan-perform suppression scan-if autonomous continue to uptake iodine

Ultrasound? Exquisitely sensitive in ascertaining the size and number

of nodules? Anatomic information vs. functional information? Cannot differentiate malignant vs. benign? Often as extension of PE resulting in “incidentalomas”

? Uses: follow-upFNA guidance- indeterminant lesions decreases

from 15% to 4% when usedmultinodular goiter

Treatment? surgery- main indications:

malignant or indeterminate cytology on FNA suspicious history/PE

if presurgical dx of malignancy- total or partial thyroidectomy (controversial)

? postoperative radioactive iodine:for high-risk (metastatic, nodal disease, gross residual disease) Target TSH is 0.5 microunits per mL or greater suppresion for high-risk

TreatmentBenign nodule- repeat biopsy (6-24mo)

- repeat biopsy if nodule enlarges/changes

- follow with clinical exams indefinitely

Hot nodule (autonomous)- with thyrotoxicosis-radioactive iodine (I131)

Patient Cases…JM-? TSH 3.22 FT4 1.28? FNA- “cyst fluid with hemosiderin laden

macrophages and epithelium favored is a brachial cleft cyst; however the presence of a rare intranuclear inclusion and mild atypia necessitates further evaluation”

? Surgical biopsy- “lymph node with metatstatic papillary thyroid cancer”

Patient Cases…

JM –Total thyroidectomy, thymectomyPost operative I131 ablation1 year post operative- NM I123 scan negativeTSH suppression with levothyroxine

Patient Cases…MK-? FNA- “scant colloid, macrophages and proteinaceous

fluid, most c/w thyroid cyst. No thyroid epithelium identified”

? US- “large complex cystic mass within the left thyroid lobe”

? FNA- “benign thyroid nodule with cystic features-hemosiderin laden macrophages, colloid and mixed follicular epithelium”

? TSH 0.21 FT4 1.67? Thyroid Scintigraphy- “warm nodule corresponding

with palpable nodule, no evidence of suppression of lobes of thyroid”

References1. Welker M, Orlov D, Thyroid Nodules, American Family

Physician 2003; 6:559-5662. Mazzafarri EL. Management of Solitary Thyroid Nodule.

N Engl J Med 1993;328:553-9.3. Feld S, AACE clinical practice guidelines for the diagnosis

and management of thyroid nodules. Thyroid Task Force. Endocr Pract 1996;2:78-84

4. Singer P, Treatment Guidelines for Patients With Thyroid Nodules and Well-Differentiated Thyroid Cancer. Arch of Internal Med. 1996;156:2165-2172.

5. Herring A. Assessment of Nondiagnostic Ultrasound Guided FNA of Thyroid Nodules. J of Clin Endocr and Metabolism 2002;87-11.