Prof. S. Deivanayagam MS Professor & HOD of Surgery Madras
Medical College Carcinoma of Thyroid
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Ca. Thyroid - Types : - Primary / secondary Follicular
cell-derived Papillary thyroid cancer Follicular thyroid cancer
Anaplastic thyroid cancer Lymphocyte derived Lymphoma C-Cell
derived Medullary thyroid cancer Secondary breast, colon,
melanoma
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Differentiated Thyroid Ca. : - 85% of all thyroid cancers
Derived from follicular cells Types Papillary carcinoma Follicular
carcinoma Mixed Papillary Follicular Hurthle cell carcinoma
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Etiology & Risk factors : - Male sex Previous neck
irradiation For Hodgkins lymphoma Papillary ca. Pre-existing
lesions MNG Follicular ca. Hashimotos Papillary ca. (controversial)
Iodine deficiency Follicular ca Family H/O Familial Syndromes
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Familial Non-Medullary Thyroid ca : -
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Clinical Features : - MC presentation Painless swelling in the
neck Pain Dysphagia Stridor Rapid enlargement Hoarseness of voice
(most important) Dyspnoea, Hemoptysis (late & rare) Lateral
aberrant thyroid lymphnode mets in papillary ca. thyroid Pulsatile
bony secondaries in follicular thyroid ca.
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Papillary Thyroid Ca. : - Most common type (~80%) Young females
(mean age 30 - 40 yrs) Least malignant one of the curable
malignancies Commonly metastasize to neck nodes Distant metastasis
uncommon Minimal or occult/microcarcinoma refers to tumours of 1 cm
or less in size with no evidence of local invasiveness through the
thyroid capsule or angioinvasion, and that are not associated with
lymph node metastases
PTC Pathology : - Gross : - Multi-focal Unencapsulated but
often has pseudocapsule Microscopic : - Closely packed Papillae
Psammoma bodies Oval or elongated pale staining nuclei with ground
glass appearance Orphan Annie eye cells
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Papillae : -
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Psammoma bodies : -
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Orphan Annie Cells : -
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Orphan Annie : -
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Investigations : - USG neck To identify the lesion To
categorize the nodule To detect associated lymphadenopathy To take
guided FNAC FNAC Best first line diagnostic procedure for papillary
ca. Thyroid function test
PTC Prognostic Systems : - DeGroots classification Class I
Intra-thyroidal Cass II Cervical node mets Class III
Extra-thyroidal invasion Class IV Distant mets Most important
prognostic factor Age at diagnosis Lymph node mets No prognostic
significance
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Follicular Thyroid Ca. : - Accounts for ~10% of thyroid ca.
Common in females Mean age 40 50 yrs Common in iodine deficient
areas May coexist with MNG Metastasize to flat bones pulsatile bony
secondaries Lymph node metastasis uncommon
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FTC Bone Mets : -
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FTC Types : - Minimally invasive Capsular invasion without
involvement of surrounding parenchyma and vascular invasion (except
those within tumour) Widely invasive Surrounding parenchymal and /
or vascular invasion
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FTC Pathology : - Gross Solitary & Encapsulated Microscopic
Well differentiated cells Presence of Vascular and / or capsular
invasion FNAC & frozen section cannot distinguish between
follicular adenoma & carcinoma Minimal tissue required -
Hemithyroidectomy
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FTC Capsular Invasion : -
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TNM Classification : - Common for all differentiated thyroid
carcinomas The only TNM system to incorporate the age of the
patient Separate for differentiated, medullary and anaplastic
ca.
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TNM for DTC AJCC 7 th : - T1Tumour 2cm or less & confined
to thyroid T2Tumour 2 4 cm & confined to thyroid T3 Tumour
>4cm or minimal extra-thyroid extension (Invasion of
sternothyroid/perithyroid soft tissues) T4aInvasion of larynx,
trachea, oesophagus or RLN T4bInvasion of prevertebral fascia or
carotid a.
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TNM for DTC AJCC 7 th : - N1aMetastasis to level VI nodes N1b
Involvement of unilateral/bilateral lateral group nodes(level I -
V) or mediastinal nodes (level VII) M0No distant metastasis
M1Distant metastasis
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TNM Stage Grouping : - AGE < 45 years IAny TAny NM0 IIAny
TAny NM1
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TNM Stage Grouping : - AGE > 45 years IT1N0M0 IIT2N0M0 IIIT1
T3N1aM0 IVT4a / T4bN1bM1
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DTC - Treatment : - Surgery remains the main stay of treatment
for DTC Types of Surgeries : - Total thyroidectomy Removal of all
thyroid tissue with preservation of parathyroids Total
thyroidectomy remains Gold standard
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Total thyroidectomy Rationale : - Total thyroidectomy Pros : -
Enables usage of RAI effectively Makes serum Tg a sensitive marker
for recurrence Enables better removal of central compartment nodes
Reduces the risk of recurrence Reduces the risk of re-operation
Total thyroidectomy Cons : - Risk of RLN injury &
hypocalcemia
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Node management in DTC : - Without lateral group enlargement
Total thyroidectomy with central compartment node dissection With
unilateral lateral group nodes mets Total thyroidectomy with MRND
With b/l lateral group nodes mets Total thyroidectomy with b/l MRND
Prophylactic neck dissection NOT indicated
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Post-op 131 I adjuvant therapy : - Specific uptake into
follicular cells Emits both particles and rays rays are therapeutic
while particles produce radiation toxicity Indications : - Positive
radio-iodine uptake scan post total thyroidectomy
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131 I ablation continued Precautions : - Stop thyroxine for 4-6
wks TSH > 30-50 mU/L for maximal effect Avoid iodinated contrast
CTs, salts & pain balms Therapeutic dose : - Low risk pt.
30-100mCi High risk pt. 100-200mCi
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Role of Chemo & Radiotherapy : - Radiotherapy - Indications
: - Unresectable disease Metastasis in support bones to avoid
fractures Painful metastasis No role for routine chemotherapy
Doxorubicin is commonly used mainly as a radiation sensitizer
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Post-op follow up : - Suppressive dose of thyroxine till TSH
95% 10yr relapse free survival Subsequent scans only if clinically
indicated Thyroglobulin : - Level >2ng/ml suggestive of
recurrence / mets Tg & anti-Tg antibodies level should be
measured every 6mth in first year, and then annually
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Hurthle Cell Ca. : - Variant of Follicular cell ca. Women >
Men Affects older age group ~65 yrs Defn. - An encapsulated group
of follicular cells with at least a 75% Hurthle cell or Oncocyte
component Large, polygonal, eosinophilic thyroid follicular cells
with abundant granular cytoplasm and numerous mitochondria -
Askanazy
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Hurthle Cell Ca : -
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Hurthle Cell Ca. continued..: - Often multicentric Diagnosis
requires demonstration of capsular and / or vascular invasion
Regional lymph nodes involved ~30% & is a poor prognostic
indicator Distant metastasis in ~15% More aggressive & poorer
prognosis
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Hurthle cell ca. Treatment : - Total thyroidectomy &
central compartment node dissection recommended MRND done in case
of enlarged lateral nodes Post op management : - Thyroid
suppression Serum thyroglobulin measurement every 6 months
Postoperative radioactive iodine is usually not effective (10%
concentrate iodine)
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Medullary Carcinoma : - Arises from Para-follicular C cells
from neural crest Constitutes 3 10 % of all thyroid cancers Types
Sporadic Hereditary (Familial or MEN II)
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Clinical features: - Symptoms due to the tumour Both lymphatic
& hematogenous spread common Paraneoplastic Syndromes Due to
secretion of calcitonin, VIP, serotonin and somatostatin Diarrhoea
most common
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Medullary Ca. - Peculiarities : - Characteristic amyloid stroma
on HPE Doesnt take up radioactive iodine Both I-131 scan and
radio-iodine ablation are of no use Serum calcitonin elevation
tumour marker Presence of lymph node metastasis is a poor
prognostic indicator
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Investigations : - FNAC USG / CT neck Calcitonin confirms the
diagnosis CEA (>50% of tumours) USG abdomen & 24hr urine
catecholamines to rule out pheochromocytoma
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Amyloid Stroma : -
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Treatment : - Without neck nodes Total thyroidectomy with
central compartment neck dissection With neck nodes Total
thyroidectomy with MRND of the involved side External beam RT
Extra-thyroidal extension(T4 disease) Unresectable / metastatic
disease as palliation Follow up serum calcitonin & CEA
monitoring
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Anaplastic Carcinoma : - Most aggressive and fortunately rarest
variety Invariably well advanced at presentation Worst prognosis
Treatment Palliative External beam RT Surgery isthumusectomy to
relieve tracheal obstruction
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Carry Home Message : - DTC carries very good prognosis and when
detected early is a curable disease Total thyroidectomy with
central node dissection is the gold standard treatment in both DTC
& MTC MRND is optional RAI ablation plays a key role in
metastatic disease in DTC