Thyroid Malignancy
Aetiology

-Mohammed Shujauddin
Introduction
• Thureoeides (Ancient Greek), meaning ‘Sheild
Shaped’.
• Anterior aspect of neck.
• Two lobes connected by i...
Embryology
• Floor of primitive pharynx, caudal to tuberculum
impar. (Marked by foramen caecum of tongue)
• Median endoder...
Anatomy
• Weight: About 25g (Larger in Females).
• Lies against C5, C6, C7 and T1 vertebrae.
• Lobes: Middle of thyroid ca...
Capsules of Thyroid
• True capsule: condensed peripheral connective
tissue of the gland.

• False capsule: derived from pr...
Relation to surrounding structures
Blood supply
• Arterial supply:
– Superior thyroid artery (ECA)
– Inferior thyroid artery (thyrocervical trunk, SCA)
– Thy...
Histology
Two types of secretory cells.
• Follicular cells:
– Columnar in active phase, cuboidal in resting phase.
– Secre...
Classification (Dunhill)
• Differentiated – 80%
– Papillary carcinoma (60%)
– Follicular carcinoma (17%)
– Paillofollicula...
Etiology
• Radiation : Proloned exposure to high dose of external
radiation or radioiodine. Children and young adults.
(pa...
– Follicular thyroid carcinoma:- agressive
• Common in females
• Iodine-deficient areas
• 50% cases with RAS oncogene muta...
– Anaplastic thyroid carcinoma:- very aggressive
• Common in women 7th to 8th decade of life.
• Undifferentiated.
• Origin...
Features

Papillary
Carcinoma

Follicular
Carcinoma

Medullary

Anaplastic
Carcinoma

Frequency

60%

17%

6%

13%

Age

a...
Thyroid malignancy etiology
Thyroid malignancy etiology
Thyroid malignancy etiology
Thyroid malignancy etiology
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Thyroid malignancy etiology

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Thyroid malignancy etiology

  1. 1. Thyroid Malignancy Aetiology -Mohammed Shujauddin
  2. 2. Introduction • Thureoeides (Ancient Greek), meaning ‘Sheild Shaped’. • Anterior aspect of neck. • Two lobes connected by isthmus. • Endocrine gland. • Regulates BMR, stimulates somatic and psychic growth, calcium metabolism.
  3. 3. Embryology • Floor of primitive pharynx, caudal to tuberculum impar. (Marked by foramen caecum of tongue) • Median endodermal thyroid diverticulum • Downward growth, bifurcates and forms lobes.
  4. 4. Anatomy • Weight: About 25g (Larger in Females). • Lies against C5, C6, C7 and T1 vertebrae. • Lobes: Middle of thyroid cartilage to IV or V tracheal ring. • Isthmus: II – IV tracheal ring. • Dimensions (cm): Lobe – 5 × 2.5 × 2.5 Isthmus – 1.2 × 1.2
  5. 5. Capsules of Thyroid • True capsule: condensed peripheral connective tissue of the gland. • False capsule: derived from pretracheal layer of deep cervical fascia. (Ligament of Berry)
  6. 6. Relation to surrounding structures
  7. 7. Blood supply • Arterial supply: – Superior thyroid artery (ECA) – Inferior thyroid artery (thyrocervical trunk, SCA) – Thyroidea ima artery (Brachiocephalic trunk or AOA) – Accessory thyroid arteries. • Venous drainage: – Superior thyroid vein – IJV – Middle thyroid vein – IJV – Inferior thyroid vein – left bracheocephalic vein – Fourth thyroid vein of Kocher – IJV.
  8. 8. Histology Two types of secretory cells. • Follicular cells: – Columnar in active phase, cuboidal in resting phase. – Secrete T3, T4. – Follicles contain colloid in lumen • Parafollicular cells (C cells): – Fewer, lie in between follicles. – Secrete thyrocalcitonin
  9. 9. Classification (Dunhill) • Differentiated – 80% – Papillary carcinoma (60%) – Follicular carcinoma (17%) – Paillofollicular carcinoma – Hurthle cell carcinoma • Undifferentiated – (20%) – Anaplastic carcinoma (13%) • Medullary carcinoma (6%) • Malignant Lymphoma - (4%) • Secondaries in thyroid (rare)
  10. 10. Etiology • Radiation : Proloned exposure to high dose of external radiation or radioiodine. Children and young adults. (papillary carcinoma) • Iodine excess and TSH – Papillary thyroid carcinoma:• • • • External radiation or radioactive iodine therapy Iodine sufficient areas. Common in children and females. RET overexpression (chr 10) – 20% cases – Tyrosine kinase receptor targeted by tumor promoting factors • NTRK1 rearrangement • Elevated TSH , Hormone dependent tumor. • Hushimotos thyroiditis
  11. 11. – Follicular thyroid carcinoma:- agressive • Common in females • Iodine-deficient areas • 50% cases with RAS oncogene mutation • Gene translocation:- PAX- 8 and PPARγ-1 • De novo or Pre-existing Multinodular goitre Hurthle cell carcinoma:variant of follicular thyroid carcinoma. Abundant oxyphill cells Spread more commonly to regional lymph nodes. Vascular or capsular invasion. – Medullary thyroid carcinoma: • Origin:- parafollicular C-cells. • Site:- Superolaterally in the thyroid lobes. • RET gene mutation, familial and sporadic • Associated with MEN II syndrome and pheochromocytoma with hypertention. MCT associated with MEN II B with pheochromocytoma (Sipple’s disease) is most aggressive. • Not TSH dependant and does not take up radioactive iodine.
  12. 12. – Anaplastic thyroid carcinoma:- very aggressive • Common in women 7th to 8th decade of life. • Undifferentiated. • Origin- dedifferentiation of differentiated PTC or FTC, or Inactivating point mutation in p53 gene. – Malignant Lymphoma • NHL type • Occurs in pre-existing Hushimoto’s thyroiditis
  13. 13. Features Papillary Carcinoma Follicular Carcinoma Medullary Anaplastic Carcinoma Frequency 60% 17% 6% 13% Age all ages Middle to old age Middle to old age; Familial Old age Female/ male ratio 2:1 3:1 1:1 1.5:1 Relation to radiation Maximum Present None Present Genetic alterations RET gene over expression RAS mutation RET mutation P53 loss Cell of origin Follicular Follicular Parafollicular Follicular Contrasting features

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