Download - Thyroid nodule evaluation
DR. SHUBHANGI
INTRODUCTIONDEFINITION- A discrete lesion
within the thyroid gland that is palpably and/or radiologically distinct from surrounding thyroid parenchyma.
INTRODUCTIONPREVALENCE- Epidemiological
studies have shown that prevalence of palpable thyroid nodule is 5% in women and 1% in men. This prevalence increases upto 19 – 67 % if detected by ultrasound.
Nodular goitre prevalence increases by age
INTRODUCTIONThe importance of thyroid nodule
rests with the need to exclude thyroid malignancy which occurs in 5 – 10 %
HOW WAS THE NODULE FOUNDPalpation with a physical exam Incidental finding on diagnostic
work upSelf detectionSurveillance Work up for symptoms of hyper or
hypothyroidism
CLINICAL EVALUATION
Predisposing factors for thyroid malignancy include: • prolonged stimulation by elevated TSH; • solitary thyroid nodule; • ionizing radiation; • genetic factors; • chronic lymphocytic thyroiditis.A nodule is more likely to be malignant if: • there is a positive family history • there is a previous history of thyroid cancer; • it is enlarging (particularly on suppressive doses ofthyroxine) ; • the nodule develops under 14 or over 65 years of age; • the patient is male; • there is a past history of ionizing radiation; • TSH is elevated; • thyroid antibodies are positive.
HISTORY1. AGE: Simple goiter- in girls approaching puberty. Both multinodular and solitary nodular goiters
as well as colloid goiters - women of 20s and 30s.
Papillary carcinoma -young girls follicular carcinoma - middle aged women. Anaplastic carcinoma - old age.
2. SEX:All types of simple goiters are far more common in females than in males.
Thyrotoxicosis is 8X more common in females than in males.
Even thyroid carcinomas are more often seen in females in the ratio 3 : 1
3. OCCUPATION:Thyrotoxicosis may appear in individuals working under stress and strain.
The patients with primary toxic goiter may be psychic.
4. RESIDENCE:Expect endemic goiter due to iodine deficiency
Certain areas are particularly known to have low iodine content in water and food. These areas are near rocky mountains.
5. SWELLING: onset, duration, rate of growth , association
with pain . Ask how the patient sleep at night.
Does she spend sleepless night?? In primary thyrotoxicosis patients often
complain of sleepless night. Whether the patient is very worried, stressed or
strained are also feature of thyrotoxicosis. Palpitations, ectopic beats and even CCF may
be noted in cases of secondary thyrotoxicosis.
secondary thyrotoxicosis-mainly cardiovascular symptoms
the primary thyrotoxicosis-mainly nervous symptoms
Sudden increase in size with pain in a goiter indicates haemorrhage inside.
The rate of growth of swelling is quite important. simple goiter/multinodular solitary nodular or
colloid goitre- grows very slowly A special feature of papillary and follicular
carcinoma of the thyroid is their slow growth. Anaplastic carcinoma however is a fast growing
swelling
6. PAINGoiter - usually painless condition. Inflammatory conditions of the thyroid
gland are painful.Malignant diseases of the thyroid gland
are painless to start with, but become painful in late stages.
In Hashimoto’s disease there is discomfort in the neck.
Anaplastic carcinoma is more known to infiltrate the surrounding structures and nerves to cause pain.
Differential Diagnosis of a Painful Thyroid: Subacute granulomatous thyroiditis Most common Hemorrhage into a goiter, tumor or cyst
with or without demonstrable trauma Less common Acute suppurative thyroiditis <1% Anaplastic (inflammatory) thyroid carcinoma <1% Hashimoto’s thyroiditis <1% TB, atypical TB, amyloidosis <1% Metastatic carcinoma
7. PRESSURE EFFECTS:Enlarged thyroid may press on the trachea to cause dyspnoeaEsophagus to cause dysphagia
Recurrent laryngeal nerve to cause hoarseness of voice
HISTORY8.h/o hyperthyroid – loss of weight in spite of good appetite, intolerance to heat, excessive sweating CNS symptoms like- irritability , insomnia, tremor of hands, muscle weakness EYE symptoms such as staring look, difficulty in closing eye, double vision ,pain in the eye (corneal ulceration)CNS and EYE symptoms are s/o primary hyperthyroidism
HISTORY
CVS symptoms like palpitations , chest pain , dyspnoea on exertion are s/o secondary hyperthyroid9.h/o hypothyroid- increase in weight in spite of poor appetite, facial puffiness, loss of hair, lethargy, poor memory, constipation, oligomenorrhoea
HISTORY10.PAST HISTORYh/o neck irradiation , h/o thyroid disease in familyThe patient should also be
asked if she was taking any drugs e.g. sulphoniuria or any Antithyroid drugs as these are goitrogenic.
11.PERSONAL HISTORY:Dietary habit is important as
vegetables of the brassica family ( eg.cabbage) are goitrogens.Persons who are in the habit of
taking a kind of sea fish which has particularly low iodine content, may present with goiter.
EXAMINATION-PHYSICAL EXAMINATION-LOCAL EXAMINATION-GENERAL EXAMINATION
PHYSICAL EXAMINATION
1. BUILD AND STATE OF NUTRITION:
In thyrotoxicosis -patient is usually thin and underweight. The patient sweats a lot with wasting of muscles.
In hypothyroidism -obese and overweight.
In case of carcinoma of the thyroid- anaemic and cachexic.
GENERAL SURVEY
2. FACE: In thyrotoxicosis one
can see the facial expression of excitement, tension, nervousness or agitation with or without variable degree of exophthalmos.
In hypothyroidism one can see puffy face without any expression
3.MENTAL STATE AND INTELLIGENCE:
Hypothyroid patients are naturally dull with low intelligence
4. SKIN:Hot and moist palm is a feature of primary thyrotoxicosis.
In myxedema the skin is dry, cool, pale and inelastic.
5. OTHER FINDINGS Rapid &Irregular pulse -feature of secondary
thyrotoxicosis.Particularly sleeping pulse rate is a very
useful index to determine the degree of thyrotoxicosis. In case of mild thyrotoxicosis it should be
below 90 In case of moderate or severe thyrotoxicosis
it should be 90 – 110 and above 110 respectively.
In hypothyroidism pulse becomes slow.
LOCAL EXAMINATIONINSPECTIONPALPATIONPERCUSSIONPALPATION
Inspection: Normal thyroid gland - not
obvious on inspection. seen only when the gland is
swollen. In case of obese and short
necked individuals inspection of the thyroid gland becomes difficult.
Pizzilo’s method - the hands are placed behind the head and the patient is asked to push his/ her head backwards against her clasped hands on the occipitus.
Ask the patient to swallow and watch for the most important physical sign – a thyroid gland moves up during deglutition.
DIFFERENTIAL DIAGNOSIS OF SWELLINGS WHICH MOVE ON DEGLUTITIONThyroid swellingThyroglossal cystSubhyoid bursitisPrelaryngeal /pretracheal
lymph nodes
In retrosternal goiter
Ask pateint to raise both arms over his head until they touch the ears.This position is maintained for a while.Congestion of face and distress becomes evident in the case of retrosternal goiter due to obstruction of the great veins at the thoracic inlet.(PEMBERTON’S SIGN)
Palpation: The gland may be palpated
from behind and from the front.
The patient seated on a stool and the clinician stands behind the patient.
The patient is asked to flex the neck slightly.
The thumbs of both hands are placed behind the neck and the other four fingers on each hand are placed on each lobe and the isthmus.
Palpation of each lobe -Lahey’s method. the examiner stands in front of the patient . To palpate the left lobe properly the thyroid gland is
pushed to the left from the right side by the left hand of the examiner.
This makes the left lobe more prominent so that the examiner can palpate it thoroughly with his right hand.
During palpation the patient should be asked to swallow in order to settle the diagnosis of thyroid swelling. Crille’s method -placing the thumb on the
thyroid gland while he patient swallows
During palpation the following points should be noted:
Whether whole gland enlarged or swelling is localised surface - smooth (primary thyrotoxicosis or
colloid goiter)-bosselated (multinodular goiter) its consistency whether uniform or variable. firm in primary thyrotoxicosis,Hashimoto’s
disease etc. slightly softer in colloid goiter Hard in Riedel’s thyroiditis or carcinoma
The mobility should be noted in both horizontal and vertical planes.
Fixation means malignant tumor or chronic thyroiditis To get below the thyroid gland is an
important test to discard the possibility of retrosternal extension.
Clinicians index finger placed on the lower border of the thyroid gland &The patient is asked to swallow.The thyroid gland will move up and the lower border is palpated carefully for any extension downwards
Pressure effectIf pressure on trachea is
suspected slight push on the lateral lobe will produce stridor (Kocher’s test).positive in multinodular goiters and
carcinoma infiltrating into trachea narrowing it.
Palpation of cervical lymph nodes.
• important in malignancy of thyroid.
• Occasionally only cervical lymph nodes may be palpable, while the thyroid gland remains impalpable.
• Papillary carcinoma of the thyroid is notorious for early lymphatic metastasis while the primary tumor remains quite small.
Percussion:This is employed over the manubrium sterni to exclude the presence of a retrosternal goiter.
This is more of a theoretical importance rather than practical
Auscultation: In primary
toxic goiter a systolic bruit may be heard over the goiter due to increased vascularity.
GENERAL EXAMINATION
In general examination one should look for:
I. Primary toxic manifestations in case of goiters affecting the young.
II. Secondary toxic manifestation in nodular goiter
III. Metastasis in case of malignant thyroid disease.
I. Primary toxic manifestations:One should look for 5
cardinal signs:a. Eye signsb. Tachycardia or increase
PR without rise in temperature.
c. Tremor of the handsd. Moist skine. Thyroid bruit
4 cardinal signs of primary toxic goiter
shown by numbers: (1) exophthalmos (2) thyroid swelling
with/without thrill (3) tachycardia (4) tremor
a.Eye signsThere are 4 important changes that may occur in the eyes in thyrotoxicosis.Lid retractionExophthalmosOphthalmoplegiaChemosis
Each one may be unilateral or bilateral
Tremor Tremor of the hands (a fine tremor) - a
primary thyrotoxic case.Ask the patient to straight out the arms in
front and spread the fingers. Fine tremors will be exhibited at the fingers
The patient is also asked to put out the tongue straight and to keep it in this position for at least ½ a minute. Fibrillary twitching will be observed
In severe cases the tongue and fingers may tremble
II. Secondary thyrotoxicosis May complicate multinodular goiter or
adenoma of the thyroid The cardiovascular system is mainly affected. Auricular fibrillation is quite common The heart may be enlarged Signs of cardiac failure such as oedema of the
ankles, orthopnea, dyspnoea while walking up the stairs may be observed.
Exophthalmos and tremor are usually absent Patients in this group are generally elderly
iii.Search for metastasiscommon in thyroid carcinoma
particularly the follicular type.The skull, spine, ends of long bone
and pelvis should be examined for metastatis
Lastly metastatis in the lungs, which is not uncommon should also be excluded.
WORK UP
THE AMERICAN THYROID ASSOCIATION (ATA) GUIDELINES FOR THYROID NODULE 2015
Nonpalpable nodules detected on US or other anatomic imaging studies are termed incidentally discovered nodules or ‘‘incidentalomas.’’
Nonpalpable nodules have the same risk of malignancy as do sonographically confirmed palpable nodules of the same size.
nodules >1 cm should be evaluated, since they
have a greater potential to be clinically significant cancers.Occasionally, there may be nodules <1
cm that require further evaluation because of clinical symptoms , associated lymphadenopathy, if size is changing
SERUM TSH Low TSH may be associated with
functioning nodule, very unlikely to be malignant
TSH has trophic effect on thyroid cancer growth mediated by TSH receptors on tumor cells
Physical exam findings that increase the concern for malignancy include:• Nodules larger than 4 cm in size (19.3% risk of malignancy (10))• Firmness to palpation• Fixation of the nodule to adjacent tissues• Cervical lymphadenopathy• Vocal fold immobility
ULTRASOUND SCANThyroid US can answer the following questions: Is there truly a nodule that corresponds to
an identified abnormality? How large is the nodule? What is the nodule’s pattern of US
imaging characteristics? Is suspicious cervical lymphadenopathy
present? Is the nodule greater than 50% cystic? Is the nodule located posteriorly in the
thyroid gland? These last two features might decrease
the accuracy of FNA biopsy performed with palpation
Normal thyroid – homogenous, medium gray echotextureOn transverse sections it is found b/w common carotid artery & trachea
Iso / hyper echoic Coarse calcifications Thin, well defined
halo Regular margins Hypovascular No lymph nodes
BENIGN Hypo echoic Micro calcifications Thick or absent halo Irregular margins Hypervascular Lymphadenopathy Taller than wide lesion
MALIGNANT
Reported sensitivities and specificities of sonographic characteristics for detection of thyroid cancer Median Sensitivity Median SpecificityMicrocalcifications 52% 83%Absence of halo 66% 54%Irregular margins 55% 79%Hypoechoic 81% 53%Increased intranodular flow 67% 81%
HYPOECHOIC
ATA Nodule sonographic patterns and risk of malignancy
HYPERVASCULARITY
CALCIFICATIONS, POORLY DEFINED, IRREGULAR MARGINS
FNACFNA is the most accurate and cost-
effective method for evaluating thyroid nodules
25-27 gauze no. needle is used
INDICATIONS A nodule that appears iso- or hypofunctioning on
radionuclide scan should be considered for FNA based on US findings
Incidental thyroid nodules (incidentalomas) are detected by fluorodeoxyglucose–positron emission tomography (18FDG-PET), sestamibi, US, CT, and MRI scans
Lesions with a maximum diameter greater than 1.0 to 1.5 cm should be considered for biopsy unless they are simple cysts or septated cysts with no solid elements.
A nodule of any size with sonographically suspicious features
INDICATIONS FOR US GUIDED FNAC Non palpable or difficult to
palpate nodule Previous non diagnostic
cytology Nodules with previous
benign cytology which has grown in size
Target specific areas: particularly important in partilly cystic nodules
In large solid nodules it ensures that different areas of nodule are sampled
FNAC RESULTS
Nondiagnostic or unsatisfactory FNA
Those biopsies that fail to meet the established quantitative or qualitative criteria for cytologic adequacy (i.e., the presence of at least six groups of well-visualized follicular cells, each group containing at least 10 well-preserved epithelial cells, preferably on a single slide)
Constitute 2-16% of all FNA samples
BENIGN-55-74% of all FNA
an adequately cellular specimen comprised of varying proportions of colloid and benign follicular cells arranged as macrofollicles and macrofollicle fragments
INDETERMINATE CYTOLOGY
-AUS/FLUS-2%–18% of nodules - Follicular neoplasm- 2%–25% - SUSP - 1%–6%
use of molecular markers in indeterminate thyroid FNA specimens is diagnostic
The largest studies of preoperative molecular markers inpatients with indeterminate FNA cytology have respectivelyevaluated a seven-gene panel of genetic mutations and rearrangements (BRAF, RAS, RET/PTC, PAX8/PPARc),a gene expression classifier (167 GEC; mRNA expression of 167 genes) , and galectin-3 immunohistochemistry (cell blocks)
For nodules with AUS/FLUS cytology, after consideration of worrisome clinical and sonographic features - such as repeat FNA o rmolecular testing
If repeat FNA cytology, molecular testing, or both are
not performed or inconclusive, either surveillance or diagnosticsurgical excision- Thyroid lobectomy
Diagnostic surgical excision is the long-established standard of care for the management of FN/SFN cytology nodules.
If the cytology is reported as suspicious for papillarycarcinoma (SUSP), surgical management should be similarto that of malignant cytology
2%–5% as definitively malignant
Malignant: PTC.these malignantfollicular cells have crowded, enlarged nuclei. Their chromatin is pale, the nuclei are irregularin contour, and nuclear grooves are prominent. These features are characteristic of PTC
Ultrasound elastography (USE)
Elastography is a measurement of tissue stiffness
As a steady pressure is applied to the thyroid gland, the degree of deformity of the underlying tissue is measured.
This technique takes advantage of the fact that malignant nodules tend to be harder than benign nodules and thus deform less compared with the surrounding normal thyroid parenchyma
LIMITATIONS Limited to PCTOperator dependant & need operator
expertise
Papillary cancer evaluated with elastography in a 56-year-old woman. Transverse US of the left thyroid lobe shows a hypoechoic nodule. Elastography shows that the nodule displays predominantly a blue shade indicating that it is stiffer then the surrounding normal thyroid. FNAB of the thyroid nodule yielded cells diagnostic for papillary thyroid cancer.
THYROID SCAN to determine if a thyroid nodule is functioning Radioisotopes used – technetium (99mTc), 123I, and
131I In hot nodule, refer to endocrinologist for further
management (5% of all nodules , risk of malignancy <1%)
In cold nodule ,10 % possibility of malignancy. FNAC is advised (80-85% of nodules)
CT Scan To know the relation to adjacent
structures like trachea, larynx, esophagus, CCA, IJV
Retrosternal extension Assess palpable and impalpable
cervical adenópathy Tracheal invasion Local and distant metastatic
deposits(Pulmonary) Abdominal CT : Lymphoma staging
and Pheochromo cytoma
Caution: Iodinated contrast to be avoided
MRI Good inherent Soft tissue contrast Excellent to image lingual thyroid Hypervascularity on MRI suggests Grave’s
disease and differentiates from Hashimoto’s disease
To assess thyroid volume Better tumor and muscle interface Lymph node assessment Since fibrous tissue short T2 weighted
relaxation time/signal density
Focal [18F]fluorodeoxyglucose positron emission tomography (18FDG-PET) uptake within a sonographically confirmed thyroid nodule conveys an increased risk of thyroid cancer, and FNA is recommended for those nodules >1 cm.
Diffuse 18FDG-PET uptake, in conjunction with sonographicand clinical evidence of chronic lymphocytic thyroiditis, does not require further imaging or FNA18FDG-PET positive thyroid nodules proved to be cancerous with higher mean maximum standardized uptake value in malignant compared to benign nodules (6.9 vs. 4.8, p < 0.001).
18FDG-PET- CT
Thyroid nodules are common entities that a thyroid surgeon must evaluate.
Nodules are foundthrough physical exam, or incidentally through imaging modalities performed for other reasons.
Ultrasound is the primary study by which the thyroid gland is imaged.
Nodules one centimeter or larger or sonographically suspicious subcentimeter nodules warrant cytologic analysis through fineneedle aspiration biopsy (FNAB) to determine the risk of malignancy.
Molecular biomarkers have shown great promise in their ability to detect malignancy in FNAB specimens,.
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