Findings from palpation alone suggest that the prevalence of thyroid nodules
in the general population ranges from 4% to 7%.
The prevalence of thyroid cancer in patients undergoing fine-needle aspiration
biopsy is estimated to be about 4-5%.
TESTS in Thyroid Nodule
Fine-needle aspiration biopsy is the single most important procedure
for differentiating benign from malignant thyroid nodules.
Lab tests as Serum TSH, FT4, T3, ESR; & if indicated thyroid
peroxidase antibodies, thyroglobulin antibodies.
Thyroid Ultrasound (cyst or mass), scintigraphy ("cold" or "hot" nodule),
and radioiodine scanning RAIU, together with measurement of various tumor
markers, are useful adjuncts in the preoperative and postoperative management
of patients with thyroid cancer.
CT, MRI - Sometimes used to assess nodule size or characteristics, adenopathy,
presence of calcifications, or pressure on adjacent organs
Screening of Thyroid Nodule:
Perform careful thyroid palpation in all patients whether or not they have
specific symptoms related to the thyroid.
Note that a tender thyroid nodule of acute onset suggests the presence of
a hemorrhagic cyst or an area of subacute granulomatous thyroiditis.
Be aware that a patient occasionally has a pseudogoiter,
which is an enlargement of the anterior lower neck caused by fat
deposition that masquerades as thyroid enlargement.
Highest suspicion of malignancy
Medullary thyroid cancer or multiple endocrine neoplasia
Nodule with Rapid tumor growth; Very firm nodule; Nodule
fixation to adjacent structures
Vocal cord paralysis
Enlarged regional lymph nodes
Moderate suspicion of malignancy
Age <20 or >60
History of radiation
Solitary nodule; Nodule Diameter >4 cm
Low suspicion of malignancy
No significant historical features
Soft or rubbery nodule <4 cm
Assess risk factors for thyroid nodules or thyroid
malignancy by taking a careful history.
Take a careful history directed at possible thyroid-related symptoms in all
Ask about symptoms such as hoarseness, dysphagia, neck pain,
or pressure, which may indicate the presence of a thyroid nodule or
Look for factors that increase the prevalence of thyroid nodules (e.g., age,
sex, iodine deficiency, exposure to external radiation, family history of
Although most patients with nodular thyroid disease are euthyroid, look
for symptoms of hyperthyroidism (e.g due to an autonomous hot
nodule) or hypothyroidism (e.g. due to Hashimoto's thyroiditis).
Once a nodule is discovered, assess thyroid function
and exclude malignancy using laboratory tests.
Iodine-123 scan (RAIU scan)
Ultrasound of thyroid
FNAB (Fine Needle Aspiration Biopsy)
Plain radiography, CT, MRI - Sometimes used to assess nodule size or
characteristics, adenopathy, presence of calcifications, or pressure on adjacent
Calcitonin, basal and stimulated - Reserved for patients with a family history
of medullary thyroid cancer or MEN or with rapidly growing nodules
Consider early referral to a
endocrinologist specialist for FNAB of the thyroid before performing
any diagnostic imaging.
Obtain thyroid FNAB through consultation with an endocrinologist, pathologist,
Consult a radiologist or endocrinologist for guidance on ultrasonography
or ultrasound-directed FNAB.
Consider other imaging studies when obstructive
symptoms are suspected.
Serum TSH, FT4, T3
Consider CT or MRI to evaluate multinodular goiters causing pressure symptoms,
but do not perform them routinely in patients with thyroid nodules.
Consider barium swallow if there is dysphagia to exclude other causes.
Consider pulmonary function testing with flow-volume loops to assess upper
Avoid routine use of radioisotope thyroid scans.
Do not order a thyroid scan in patients with a normal or elevated serum TSH
Consider radioisotope scans for the following reasons:
To assess the function of one or more nodules in a multinodular goiter as
a prelude to possible fine needle FNAB of cold nodules within
To evaluate the size and extent of a large multinodular goiter
To look for a "hot" nodule in a patient with a suppressed TSH and a "hot"
nodule which may therefore not require FNAB
Avoid routine ultrasonography in patients with thyroid
nodules unless thyroid palpation is difficult or if the findings on palpation
Routine ultrasonography is not cost effective.
Ultrasonography will detect nonpalpable thyroid nodules (usually <1 cm
in size) in 30% to 50% of normal individuals.
The sensitivity of high-resolution ultrasonography for detecting malignancies
is 95%, but its specificity is only 18%, reflecting the fact that most nodules
Ultrasound often shows that a suspected solitary thyroid nodule is really
part of a multinodular gland, but this information is rarely helpful clinically.
Current high-resolution ultrasonography is sensitive, having the ability
to identify nodules as small as 2 mm in the gland.
Microcalcifications within a nodule suggest papillary thyroid carcinoma.
Diagnosis of Thyroid Nodules
Enlarging, firm neck mass; often bilateral Classically seen in older women
with a history of Hashimoto's thyroiditis
Thyroid cyst or Thyroid adenoma
Firm or hard, tender thyroid; may be unilateral Usually seen in association
with thyroidal tenderness, systemic symptoms of fever and malaise; characterized
by elevated sedimentation rate and very low radioiodine uptake
Thyroglossal duct cyst
Midline cystic mass at level of hyoid bone May become infected; rarely malignant
Pyramidal lobe of hyoid
An isthmic projection of thyroglossal duct May be palpable in autoimmune
Lymph nodes in midline above the thyroid May be involved and enlarge in thyroid
Soft mass in the suprasternal notch
Pulsatile mass Seen in elderly patients; not a sign of aneurysmal dilatation
Firm, matted, fixed anterior cervical nodes May be associated with malignancy,
including thyroid cancer
Soft, resilient mass interior to upper one third of eidomastoid Usually seen
in adults; cyst fluid contains cholesterol crystals
Carotid body tumor
Cystic or hard mass at carotid bifurcation Use caution; may produce bradycardia
or dizziness with pressure on the tumor
- most common variety, 60-70% of thyroid tumors. May be associated
with radiation exposure. Tumor contains psammoma bodies.
- Metastasizes by lymphatic route (30% at time of diagnosis).
- 10-20% of thyroid tumors. The incidence has been decreasing since the addition
of dietary iodine. It occurs usually in females over 40 years of age.
- Metastasizes by the hematogenous route.
Hurthle cell carcinoma
- usually in patients over 60 years of age. Radioresistant. Composed of distinct
large eosinophilic cells with abundant cytoplasmic mitochondria.
- arises from parafollicular cells, C-cells. 2-5% of all thyroid tumors.
25-35% are associated with multiple endocrine neoplasia (MEN) syndromes which
can be familial or sporadic. Calcitonin is a chemical marker.
is found in about 5% of patients with thyroid malignancy.
About three fourths of patients with medullary cancer have the "sporadic"
form, whereas the other 25% have a hereditary form that may be part of the
multiple endocrine neoplasia type 2 (MEN-2) syndromes.
In medullary thyroid cancer, nodal metastatic involvement is associated with
increased risks for both recurrence and death .
- 3-5% of thyroid tumors, usually in patients over 60 years of age
-Anaplastic cancer, which is the most aggressive known solid tumor
of any organ, has a rapid and relentless course and can cause death within
months of diagnosis.
Other - lymphoma, sarcoma, or metastatic (renal, breast or lung)
Fine-Needle-Aspiration Biopsy Results
Benign (negative): Colloid nodule, Hashimoto thyroiditis, subacute
(granulomatous) thyroiditis, cyst
Suspicious ((indeterminate): Follicular neoplasm, Hürthle
cell neoplasm, other findings that suggest (but are not diagnostic of) malignancy
Malignant (positive): Papillary carcinoma, medullary carcinoma,
anaplastic carcinoma, metastatic carcinoma
Nondiagnostic (unsatisfactory): Foam cells only, cyst fluid
only, too few follicular cells, excessive air drying, too much blood
of Thyroid Nodule
Some of the Indications for Thyroid Nodule Surgery:
A malignant or suspicious thyroid nodule on FNAB.
Consider primary lobectomy for benign nodules.
COnsider surgery when there is continued nodule growth, despite benign FNAB
Consider near-total thyroidectomy for papillary or follicular carcinoma.
Consider bilateral subtotal thyroidectomy for multinodular goiters.
Consider surgery in patients who have benign cytology on FNAB but who
have compressive symptoms, fears about the possibility of cancer, and/or
Consider surgical treatment for certain benign nodules.
Consider surgical treatment for solitary benign nodules
There is continued nodule growth despite benign FNAB results
Cytology is benign but the clinical impression is suspicious (i.e., there
is growth, the patient is aged <20, and there is a history of radiation
There are compressive symptoms (e.g., dysphagia, shortness of breath, hoarseness)
from a large nodule or multinodular goiter
Solid or cystic lesions remain nondiagnostic on repeated biopsies
There are cosmetic considerations
For single benign nodules, consider primary lobectomy with or without
If a malignancy is discovered intraoperatively or on final pathology, consider
Recognize that T4-suppression therapy remains
controversial and is not recommended.
Recognize that T4 therapy is not recommended for most patients with thyroid
Note that T4 therapy might be considered in a patient with a benign nodule
cytology whose nodule is enlarging.
To avoid untoward effects of excessive T4, ensure that the target serum TSH
level is not <0.2 to 0.3 mIU/L.
In postmenopausal women, be sure that T4-suppressive therapy is accompanied
by calcium supplementation and possibly even estrogen therapy, particularly
if BMD is >2 SD below normal.
T4 therapy may be effective in decreasing the size of benign thyroid nodules
that occur in patients with a history of external-beam radiotherapy.
TSH may not be the dominant growth factor in nodule growth; thus, suppressing
it with thyroid hormone may not be effective in shrinking thyroid nodules.
Early reports that suggested the effectiveness of T4-suppressive therapy
were generally uncontrolled studies.
Overall, <20% of thyroid nodules seem to respond to T4-suppressive
TSH suppression in elderly, otherwise healthy individuals increases the risk
of atrial fibrillation threefold (106), increases bone loss (103; 107), and
possibly increases fracture rates in postmenopausal women