Evaluation of Thyroid Nodules

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Evaluation of Thyroid Nodules

• Michael L. Tuggy, MD
• Swedish Family Medicine, Seattle, WA

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Case 1

• 42 y.o. male with no active medical problems.
  During your routine physical, note a thyroid
  nodule. Told by ENT last year not to worry about
  it.
• PE 1 x 2cm R lower pole nodule.
• What information do you want from the patient?

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Age as a Risk Factor

• Age
• young patients (lt20 years of age)
• thyroid nodules are much more likely to be
  malignant (40-50).
• elderly (gt60 years of age) -higher risk,
  especially of more aggressive thyroid tumors.

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Gender and Thyroid Nodules

• Gender
• male -higher risk if nodule present
• females
• have many more nodules
• less likely to be malignant.
• still have majority of thyroid cancers

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Other major risks

• Radiation to head and neck.
• 40 risk of thyroid cancer usually 25 years
  later.
• Exposed populations- Polynesian studies
• Family History of MEN II, Gardners Syndrome,
  Cowdens disease.

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Historical Red Flags

• Recent growth
• Soft tissue swelling
• Vocal changes
• Dysphagia
• Signs of thyroid dysfunction

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Case 2

• 26 y.o. Eritrean female with a 2-3 year history
  of goiter. No symptoms but noted enlargement on
  right for 1 year.
• P.E. 3x4 cm Right sided thyroid mass, firm,
  adherent to soft tissue.
• What physical findings are worrisome?
• How can you best clarify the nature of the nodule?

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Thyroid Exam
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Physical Exam of the Thyroid

• Use both hands simultaneously to evaluate for
  symmetry
• Patient upright - screening exam
• Patient supine with neck in extension- detailed
  exam. Swallowing assists in elevating gland.
• Evaluation of other neck structures.
• Voice changes (recurrent laryngeal nerve).

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Thyroid Scans

• Purpose
• Determine function of the gland and/or a nodule
  within the gland
• Hot nodules - usually independently functioning
  nodules
• Rarely, rarely malignant
• Cold nodules - either adenoma or maligancy
• 15 chance of malignancy in adults.

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Thyroid Ultrasound

• Can identify presence of nodules.
• May be able to characterize follicular vs. solid.
• Not able to rule our malignant nodule
• Aid in biopsy.

Thyroid
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Case 3

• 30 y.o. WF with enlarging cold benign thyroid
  adenoma (diagnosis from previous FNA biopsy).
• PE 4 x 5 cm mass on Right
• What do you do now?

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Fine-Needle Aspiration

• Best tool for determining pathology other than
  surgical excision.
• Can be as high as 80 sensitive and 95
  specific.
• Operator dependent in obtaining adequate amount
  of tissue. 25 gauge needle is optimal.
• Should not be relied on if negative in patient
  with previous neck irradiation.
• Multifocal tumors common.

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Interpreting the Biopsy Report

• What you get
• benign
• indeterminate
• suspicious
• inadequate specimen
• What it means
• benign - 90-95 likelihood it is benign
• indeterminate- who knows?
• suspicious- its malignant.
• inadequate specimen - do it again (and again)

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Thyroid Malignancies- Papillary

• Most common
• 30 have node metastasis at diagnosis
• Radiation related
• Histologically, psammoma bodies distinguish from
  benign adenoma.

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Thyroid Malignancies-Follicular

• 20 of malignancies
• Distinguished from normal follicular adenomas by
  invasion of capsule or blood vessels.
• May be difficult to determine on FNA

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Thyroid Malignancies- Medullary

• 5-10 of cases
• arise from the C cells which produce calcitonin
• diagnosis based on elevated thyrocalcitonin
  levels and thyroid nodule (cold)

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Thyroid Malignancies- Anaplastic

• lt 10
• Highly aggressive with local extension at time of
  diagnosis.
• No suitable therapy
• Prognosis lt 1 yr from diagnosis

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Treatment

• For all malignancies, excision of the the lobe
  (or if post-radiation the entire gland).
• XRT- very specific and well tolerated- I131
  therapy.
• Anaplastic tumors - palliative radiation and XRT.

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What about those benign nodules?

• No specific treatment is needed.
• Thyroid suppression may shrink size of adenomas
• Not proven to be effective or necessary
• May hide malignancies - ? Periodic biopsies or
  scans.

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Case 4 - This weeks puzzler!

• 40 y.o. WF s/p I131 ablation for Graves Dz. 6
  years ago.
• Persistant R thyroid nodule 2 x 1.5 cm in size.
• What is the likely diagnosis?

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Outcomes

• Case 1. - Papillary cancer - 3 () nodes
• no metastasis at 1 year.
• Case 2. - Follicular cancer - 5 () nodes
• no metastasis at 1.5 years
• Case 3. - Large adenoma with incidental 1 cm
  papillary carcinoma superior to nodule.
• No recurrence at 5 years.
• Case 4. - Non-functional adenoma

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Modified from Castro, MR, Gharib, H. Endocr
Pract 2003 9128.
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SummarySolitary Nodule Evaluation

• TSH if low scan if hot nodule, then
  observe.
• Normal TSH - Do I scan first or FNA first?-
• high risk - scan and FNA
• Is the nodule cold or hot?
• Cold - FNA biopsy
• low risk - FNA
• if indeterminate- scan and re-FNA or excisional
  biopsy.
• Anti-perioxidase Antibody helpful if low- TSH
  to diagnose thyroiditis.

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Never assume a solitary thyroid nodule is benign.
Prove it.