Download MBBS Surgery Presentations 57 Thyroid Neoplasms Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Surgery 57 Thyroid Neoplasms PPT-Powerpoint Presentations and lecture notes


Thyroid Neoplasms

Dept. of Surgery

Introduction

? Six deaths per 1 million people occur annually.

? Occurs in about 40 per 1 million people per year

? The most common endocrine malignancy

? Accounts for 95% of all endocrine cancers

? Female to Male Ratio 2.5:1
Thyroid Neoplasms

Primary Tumours

? Epithelial
? Malignant Lymphomas
? Mesenchymal tumours

Metastatic Tumours

Epithelial Thyroid Neoplasms

? Tumours of follicular cells

? Benign (adenomas)

? Follicular adenoma

? Malignant (carcinomas)

? Follicular carcinoma (10-20%)
? Papillary carcinoma (75-85%)
? Undifferentiated (anaplastic) carcinoma (<5%)

? Tumours of C-cells

? Medullary thyroid carcinoma (MTC - 5%)
Risk Factors for Thyroid Cancer

The only wel -established risk factor for differentiated thyroid

cancer is head and neck Radiation,especial y during infancy

Papil ary thyroid carcinoma may occur in several rare inherited

syndromes, including familial adenomatous polyposis,

Gardner's syndrome, and Cowden's disease

Patient's Age and Gender

? Malignancy more common in children and adults >60

? Men

Follicular Carcinoma

? Second most common form, 10-20%

? Females > Males, average age = 45 - 55 yr

? Rare in children

? Solitary nodule, painless, cold on isotopic scan

? 50% 10 yr survival Vs 90%10 yr survival

? Haematogenous route is preferred mode of spread


Follicular Carcinoma

? Solitary round or oval

nodule

? Thick capsule
? Composed of follicles
? Capsular invasion or

vascular invasion

within or outside

capsular wall

Papillary Carcinoma

? Commonest thyroid malignancy, 75-85%

? Female:Male = 2.5:1

? Mean age at onset = 20 - 40 yr

? May affect children

? Prior head & neck radiation exposure

? Indolent, slow-growing painless mass cold on isotopic scan

? Cervical lymphadenopathy may be presenting feature


Papillary Carcinoma

? Variable size

(microscopic to

several cm)

? Solid or cystic
? Infiltrative or

encapsulated

? Solitary or multicentric

(20%)

Papillary Carcinoma

Nuclear Features

? Optically clear (ground

glass, Orphan Annie)

nuclei

? Nuclear

pseudoinclusions or

nuclear grooves
Papil ary Carcinoma Prognosis

Excellent but following factors play important role:

? Age and sex

? Size

? Multicentricity

? Extra-thyroid extension

? Distant metastasis

? Total encapsulation, pushing margin of growth & cystic

change

Anaplastic Carcinoma

? Rare; < 5% of thyroid carcinomas

? Highly malignant and general y fatal < 1yr.

? Elderly 65 yrs; females slightly > males

? Rapidly enlarging bulky neck mass

? Dysphagia, dyspnoea, hoarseness


Anaplastic Carcinoma

? Large, firm, necrotic mass

? Frequently replaces entire thyroid gland

? Extends into adjacent soft tissue, trachea and oesophagus

? Highly anaplastic cell on histology with:

? Giant, spindle,small or mix cell population

? Foci of papillary or follicular differentiation

Anaplastic Carcinoma

? Cellular pleomorphism
? +/- multinucleated

giant cells

? High mitotic activity
? Necrosis
Medullary Thyroid Carcinoma (MTC)

? Malignant tumour of thyroid C cel s producing Calcitonin

? 5 % of al thyroid malignancies

? Sporadic (80%)

? Rest in the setting of MEN I A or B or as familial without
associated MEN syndrome

Medullary Thyroid Carcinoma (MTC)

Sporadic MTC

? Middle-aged adults
? Female:male = 1.3:1
? Unilateral involvement of gland
? +/- cervical lymph node metastases
? Indolent course with 60-70% 5-yr survival after

thyroidectomy


Multiple Endocrine Neoplasia Types IIA & IIB

? Germ-line mutation in Ret protooncogene on

chromosome 10q11.2

? MEN IIA: MTC, phaeochromocytoma, parathyroid

adenoma or hyperplasia

? MEN IIB: MTC, phaeochromocytoma, mucosal

ganglioneuromas, Marfanoid habitus, other skeletal

abnormalities

Medullary Thyroid Carcinoma (MTC)

? Histology same for

sporadic & familial

? Solid, lobular or

insular growth

patterns

? Tumour cells round,

polygonal or spindle-

shaped

? Amyloid deposits in

many cases


Medullary Thyroid Carcinoma (MTC)

? Amyloid deposits stain

orange-red with

Congo Red stain

Clinical Manifestation

? Most patients are euthyroid and present with a

thyroid nodule

? Symptoms such as dysphagia, dyspnea and

hoarseness usually indicate advanced disease

? Ipsilateral Cervical lymph glands may also be present.


Diagnosis

? Serum TSH

? Fine Needle Aspiration Cytology (FNA)

? High Resolution Thyroid US- helpful in detecting
non palpable nodule and solid versus cystic lesion

? Thyroid Isotope Scanning- to assess functional activity

of a nodule

Fine Needle Aspiration

? Procedure of Choice ? Fast, minimal y invasive and few

risk

? Incidence of False positive: 1%

? Incidence of False negative: 5%

? FNA is not a tissue diagnosis

? Limitation of FNA: cannot distinguish a benign fol icular

from a malignant lesion.




FNA Results of Thyroid Nodule
Staging For Differentiated Thyroid Cancer

In differentiated thyroid carcinoma, several classification

and staging systems have been introduced. However, no

clear consensus has emerged favoring any one method

over another

? AMES system/AGES System/GAMES system

? TNM system

? MACIS system

? National Thyroid Cancer Treatment Cooperative Study

(NTCTCS)

Prognosis

? GAMES scoring (Papil ary & Fol icular Cancer)

? G Grade

? A Age of patient when tumor discovered

? M Metastases of the tumor (other than Neck LN)

? E Extent of primary tumor

? S Size of tumor (>5 cm)

The patient is then placed into a high or low risk

Category

Age for poor prognosis has been raised from 45 to 55 years (AJCC 8th

Edition)


(GAMES)

Prognosis of Thyroid Carcinomas

Papillary

Best prognosis

Follicular

Medullary

Anaplastic

Worst prognosis
H?rthle Cell Neoplasms

? More aggressive than other differentiated thyroid carcinomas

(higher mets/lower survival rates)

? Decreased affinity for I131
? Need to differentiate from benign/malignant

? 65% of tumors > 4cm are malignant

? If malignant, needs total thyroidectomy and I131 with thyroglobulin

assays

? Mets may be more sensitive to I131 than primary

Secondary Tumours

Direct extensions from: larynx, pharynx, oesophagus


Metastasis from: renal cell carcinoma, large bowel carcinoma,
malignant melanoma, lung carcinoma, breast carcinoma
Treatment

The main treatment of papillary carcinoma of the thyroid is

surgical resection.

For lesions <1 cm, there is general agreement in the literature

that lobectomy plus isthmectomy is the appropriate treatment.

For adults with lesions larger than 2 cm, a total thyroidectomy is

favored by most surgeons.

Patients with history of exposure to ionizing radiation of the

head and neck should have total thyroidectomy

Controversies in Treatment

Total Vs Lobectomy

? Controversy exists about the use of total thyroidectomy

versus lobectomy and isthmectomy in adults with a 1-

to 2-cm lesions

? Role of Lymph node dissection also debated
Central Lymph Node Dissection

Central compartment =the region bounded by the
jugular veins, the hyoid bone, and the sternal notch

All central nodes removed at time or procedure

Removal of Central Nodes important in medullary and

Hurthle Cell Ca

? Microscopic spread is high
? Do not take up I131 and cannot be ablated

Lateral Lymph Node Dissection

Diseased nodes lateral to the jugular vein =modified
radical neck dissection

Removal of LN's anterior and posterolateral to the IJV from
the mastoid to the subclavian vessels inferiorly and lateral y
to spinal accessory nerve (Level 2-5)

Sparing the internal jugular vein, spinal accessory nerve,
and sternocleidomastoid muscle


Treatment

Complications of Surgery

Hypocalcemia -devascularization of parathyroid

about 5%, which resolves in 80% of these cases in about 12

months

Recurrent Laryngeal Nerve Injury-either traction
induced or division.

less than 3%

Bleeding

wound hematomas
Postoperative management for

thyroid cancer

Two principles:

? Radioiodine remnant ablation

? Adminstration of Thyroid Hormone

? To suppress TSH and growth of any residual thyroid

? To maintain patient euthyroid

? Maintain TSH level 0.1uU/ml in low risk pts

? Maintain TSH Level < 0.1uU/ml in high risk pts

Postoperative RAI

Recommendations:
? Postoperative remnant ablation for al patients with

differentiated thyroid carcinoma 45 years of age or older

? Those with primary tumor 1.5 cm in diameter or more

? Extrathyroidal disease, whether manifested by direct

invasion through the capsule of the gland or local or
regional metastases.


Radioiodine therapy

The nonsurgical treatment for papillary thyroid

carcinoma is radioiodine (131-I).

Radioiodine has three uses in the postoperative

treatment of patients with thyroid cancer:

? ablation of residual thyroid tissue

? imaging for possible recurrent disease

? treatment of residual or recurrent thyroid cancer
External Beam Radiotherapy and

Chemotherapy

External Radiation required to control unresectable cancer.

Chemotherapy may occasionally be beneficial in patients with
progressive symptomatic thyroid carcinoma that is unresponsive
or not amenable to surgery, radioiodine therapy, or external
radiotherapy

This post was last modified on 08 April 2022