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DIFFERENTIATED THYROID CARCINOMA
ANGEL DAS
Endocrine gland – lower part of neckExtend – oblique line of thyroid to 5th or 6th tracheal ringsConsists – right & left lobes joined by isthmusCapsules – true & false
ANATOMY
Blood supply Arterial Supply• Superior thyroid arteries• inferior thyroid arteries. Venous Drainage• Superior• middle • inferior thyroid veins.
PHYSIO LOGY-
The primary ph ysiologic role is the production of thyroid h ormone, which plays an im portant role in metabolic homeostasis.
A secondary role is the production of calcitonin, a horm on e involved in calcium hom eostasis.
The follicular cells of th e thyroid gland synthesize and secrete thyroglobulin(Tg) and thyroid hormone in two biologically active form s,
thyroxine (3,5,3′,5′ iodothyronine or T4) and
triiodothyronine (3,5,3′ iodothyronine or T3).
T4 is considered the storage and transport form of the hormone and T3 is considered the metabolically active form.
CLASSIFICATION OF THYROID TUMORSBENIGN MALIGNA
NTFollicular adenoma
primary secondary
Parafollicular cells
Lymphoid cells
-Metastatic-Local infiltration-
follicular-papillary
-anaplastic
-medullary
-lymphoma
Differentiated
Undifferentiated
DIFFERENTIATED THYROID CARCINOMA
Tumors derived from follicular cells9o% of all thyroid malignanciesMost common presentation – Solitary thyroid nodule
Papillary CarcinomaAetiopathogenesisRadiation therapy- in childhood for adenoids,
thymus enlargement,
hemangiomasHashimoto thyroiditis
Familial
Genetic - chromosomal rearrangement fusion protein RET/PTC Mutational activation of BRAF gene Activation of
MAP kinase pathway
Altered gene expression
Uncontrolled growth
80% of thyroid malignancy
Commoner in females and younger age group
Lymphatic spread is common
Multiple foci in same lobe
GrossFeatures
Papillary projections
Orphan Annie eye nuclei
Psammoma bodies
Histology
Clinical features …..
o Compression features are less common
o Metastasis to cervical lymph node
o Microcarcinoma < 1cm
o Young females (20-40 years)
o soft / hard / firm ,solitary / multifocal swelling
Follicular carcinomaAetiopathogenesisDeficiency of dietary iodinePre existing multinodular goitreGenetic factors - Fusion of PAX8 gene to
PPAR gamma
10% of thyroid carcinoma
Common in women & older age group(40-60yrs)
Distant metastasis through blood into bones,lungs & liver
Bone secondaries – vascular, warm, pulsatile commonly in skull, long bones & ribs
Most common presenting feature – solitary thyroid nodule
Morphology
Minimally invasive – grossly
encapsulated
Widely invasive – may be
unencapsulated
• Capsular & vascular invasion
CLINICAL FEATURES . . . solitary thyroid nodule - firm/ hard
Stridor – tracheal compression / infiltration
Dyspnoea, hemoptysis, chest pain – lung secondaries
Hoarseness of voice – recurrent laryngeal nerve
involvement
F : M = 3: 1
Hurthle cell Carcinoma -more aggressive variant of follicular ca. -contain oxyphil cells
-They secrete thyroglobulin
-metastasize to local lymph nodes
-potentially malignant.
InvestigationsSerum TSH - Papillary Carcinoma
Thyroid imaging• Radionuclide Imaging – using radiolabelled iodine 123I / Technetium
FNAC -with /without ultrasound guidance -inconclusive in follicular carcinoma
Ultrasound -evaluation of thyroid nodule -provide information about size & multicentricity
CT/MRI -excellent image of thyroid gland & nodes -relationship with airway & vascular structures
PET scan -clinically occult thyroid carcinoma
Chest & Thoracic inlet X ray - confirm clinically important degrees of tracheal deviation - Pulmonary metastasis detected
Skull X ray
Lytic lesions
TNM StagingNODES N0 – No regional node metastasis N1a – level VI N1b – any other levels
METASTASIS M0 – No metastasis M1 – metastases present
Stage Under 45 yrs Over 45 yrsI Any T, any N, M0 T1 , N0, M0II Any T, Any N, M1 T2, N0, M0III T3/T1, T2 & N1a M0IVA T4/T1,T2,T3T4a&
N1b, M0IVB T4b, Any N, M0IVC Any T, Any N, M1
Tx-ThyroidectomyRose position
Kocher’s incision
Total thyroidectomy recommendations- If the papillary thyroid carcinoma is >1 cm Follicular adenoma > 4cm Multifocal disease Regional or distant metastases are present, The patient has a personal history of radiation therapy
to the head and neck The patient has first-degree family history of DTC.
Older age (>45 years) – near-total or total thyroidectomy - tumors <1–1.5 cm
Surgical Treatment
Hemithyroidectomy small (<1 cm), low-risk, unifocal, absence of
• prior head and neck irradiation• radiologically or clinically involved
cervical nodal metastases.
Lymph Node Dissection
Therapeutic central-compartment (level VI) neck dissection - clinically involved central or lateral neck lymph nodes
Prophylactic central-compartment neck dissection (ipsilateral or bilateral) – advanced papillary thyroid carcinoma (T3 or T4).
Not needed small (T1 or T2), noninvasive, clinically node-negative PTCs and most follicular cancer.
Modified Radical Neck Dissection – metastasis to lateral cervical lymph nodes
Post-Operative Management of Differentiated Thyroid Carcinoma
Radioiodine therapy - reduces recurrence & metastasisThyroxine- 0.1-0.2mg to suppress endogenous TSH productionThyroglobulin -
Complications Hemorrhage
Recurrent laryngeal nerve palsy
Hypoparathyroidism
Hypothyroidism
Injury to external laryngeal nerve
Thank you