thyroid carcinoma

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      • Benign thyroid tumours
        • Most are follicular adenomas (MCQ)
        • All papillary tumours should be considered malignant
      • Follicular adenoma
        • Of all follicular lesions – 80% benign and 20% malignant (MCQ)
        • They are smooth and discrete lesions with glandular or acinar pattern
        • They are encapsulated and usually 2-4 cm in diameter
        • Adenomas can not be differentiated from carcinoma on FNA cytology
        • Requires histological assessment of capsular invasion(MCQ)
      • Toxic adenoma
        • Account for 5% of cases of thyrotoxicosis
        • Female : Male ratio is approximately 9:1(MCQ)
        • Presentation
          • 54% with a nodule(MCQ)
          • 37% with thyrotoxicosis
          • 95% of toxic adenomas are benign(MCQ)
        • Thyrotoxicosis not usually associated with eye signs(MCQ)
        • A hot nodule on scintigraphy with suppression of normal thyroid uptake(MCQ)
        • Treatment is by thyroid lobectomy(MCQ)
        • Require post operative thyroxine until suppressed gland returns to normal(MCQ)
      • Malignant thyroid tumours
        • Differentiated thyroid cancer accounts for 80% of thyroid neoplasms
        • Female : male ratio is approximately 4:1(MCQ)
        • Usually presents as solitary thyroid nodule in young or middle age adult
        • Nodule more likely to be malignant in man or child
      • Papillary and mixed tumours
        • 50% tumours are less than 2 cm diameter at presentation(MCQ)
        • Tumours < 1 cm diameter regarded as minimal or micropapillary lesions(MCQ)
        • Characteristic histological features(MCQ)
          • Psammoma bodies
          • ‘orphan Annie’ nuclei
        • 30 – 50% are multicentric with simultaneous tumour in contralateral lobe
        • Early spread occurs to regional lymph nodes
        • ‘Lateral aberrant thyroid’ almost always metastatic papillary carcinoma(MCQ)
        • Thyroid lobectomy adequate for minimal lesions (MCQ)
        • Total thyroidectomy is otherwise surgery of choice(MCQ)
        • Many tumours are TSH dependent
        • TSH suppression with post-operative thyroxine appropriate
        • Post operative Thyroxine reduces recurrence and improves survival
        • 80% nodes have microscopic involvement(MCQ)
        • The role of prophylactic lymph node dissection at time of initial surgery is unclear
        • Lymph node dissection does not improve survival(MCQ)
        • Alternative is to sample the lymph nodes.
          • If no evidence of nodal metastasesno further surgery
          • If nodal metastases presentmodified neck dissection
      • Follicular tumours
        • Can not differentiate follicular adenoma and carcinoma on FNA cytology (MCQ)
        • Treatment of all follicular neoplasms is thyroid lobectomy with frozen section (MCQ)
          • If frozen section confirms carcinomaTotal thyroidectomy
          • If frozen section confirms adenomaNo further surgery required
        • Total thyroidectomy allow detection of metastases using 123I Scanning during follow up(MCQ)
        • All patients require suppressive thyroxine therapy

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      • Follow up of thyroid carcinoma
        • Annual 123 I scanning to detect asymptomatic recurrence
        • Treatment of such recurrence can still be curative
        • Need to be off T4 for at least one month with conversion to T3
        • Serum Thyroglobulin – increasing levels often first sign of recurrence (MCQ)
        • May allow detection of recurrence without inconvenience of scintigraphy
      • Total thyroidectomy versus. thyroid lobectomy for differentiated tumours
        • Points in favour  for total thyroidectomy (MCQ)
          • Multifocal disease occurs in opposite lobe in 50% cases
          • Total thyroidectomy reduces risk of local recurrence
          • Ablation with radioiodine is facilitated
          • Serum thyroglobulin can be used as a tumour marker for progression or recurrence
          • In experienced hands, morbidity of total thyroidectomy is low
        • Points in favour  for thyroid lobectomy (MCQ)
          • Many patients do not require radioiodine
          • Progression to undifferentiated carcinoma is rare
          • Significance of micro-foci in contralateral lobe is uncertain
          • No evidence that more extensive procedure is associated with better prognosis
          • Higher incidence of hypoparathyroidism after total thyroidectomy
      • Anaplastic carcinoma
        • Accounts for less than 5% thyroid malignancies
        • Occurs in elderly
        • usually an aggressive tumour (MCQ)
        • Local infiltration causes dyspnoea, hoarseness and dysphagia
        • Thyroidectomy seldom feasible
        • Incision biopsy should be avoided as it often causes uncontrollable local spread (MCQ)
        • Radiotherapy and chemotherapy important modes of treatment(MCQ)
        • Death usually occurs within 6 months
      • Thyroid lymphoma
        • Accounts for 2% of thyroid malignancies
        • Often arises with Hashimoto’s thyroiditis or non-Hodgkin’s B-cell lymphoma(MCQ)
        • Presents as a goitre in association with generalised lymphoma
        • Diagnosis can often be made by FNA cytology
        • Radiotherapy is treatment of choice(MCQ)
        • Prognosis is good – often >85% 5 year survival
      • Medullary carcinoma of the thyroid
        • Accounts for 8% of thyroid neoplasms
        • Arises from para-follicular C-cells(MCQ)
        • 20% of cases are familial
        • Autosomal dominant inheritance with almost complete penetrance
        • Can occur as part of MEN IIa and MEN IIb syndromes(MCQ)
        • 80% of cases are sporadic
        • Sporadic cases usually unilateral (MCQ)
        • 50% have lymph nodes at presentation
        • Familial cases often multifocal and bilateral
        • Tumours metastasise to nodes and via blood to bone, liver and lung
        • They produce calcitonin, calcitonin gene related peptide and CEA
        • Total thyroidectomy is treatment of choice (MCQ)
        • Calcitonin can be used in follow up for the presence of metastatic disease (MCQ)
      • Complications of thyroidectomy
      • Haemorrhage
      • Wound Complications
        • Sepsis
        • Hypertrophic scarring
      • Respiratory Obstruction
        • Laryngeal mucosal oedema
        • Clot deep to strap muscles
        • Bilateral incomplete recurrent laryngeal nerve palsies
        • Tracheomalacia
      • Nerve Damage
        • Recurrent laryngeal nerve palsy
          • Incomplete-Cord moves to midline
          • Complete-Cord in cadaveric position
        • Pre operative cord inspection is essential
        • 3% population have asymptomatic recurrent laryngeal nerve palsy
      • Hypocalcaemia
      • Pneumothorax
      • Air Embolism
      • Recurrent hyperthyroidism
      • Hypothyroidism

Clinical Pearls for MD Entrance Exam :

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      • the majority of hot nodules are benign, and approximately 5% of cold nodules are malignant. (MCQ)
      • Thyroid ultrasound is used to determine whether a nodule is solid or cystic to assess nodule size or to identify impalpable nodules.
      • Solid nodules are more likely to be cancerous than are cystic lesions. (MCQ)
      • For patients suspected of having medullary cancer based on family history, serum calcitonin levels should be checked after a calcium-pentagastrin infusion test.
        • An elevated calcitonin level defines a positive result and obviates the need for FNA. (MCQ)
      • One option for lesions deemed benign on FNA is hormone suppression: (MCQ)
        • if regresses then follow
        • If grows remove
        • if same repeat FNA
      • Surgical management (MCQ)
        • Lobectomy:
          • unclear path (go back for completion, if necessary)
        • Lobectomy + isthmusectomy:
          • papillary < 1 cm, benign unilateral lesions or suspicious lesions
        • Total thyroidectomy (followed by RAI):
          • papillary ≥ 1 cm, follicular, Hürthle, medullary
        • IF planning postop RAI (MCQ)
          • must do total thyroidectomy, regardless of size (RAI only useful in well differentiated cancersnot MTC)
        • Medullary is the only histology where you do central dissection (level VI and VII) prophylactically (in addition to total thyroidectomy) and modified radical neck dissection (levels II – V) on affected side (MCQ)
        • Performing a total thyroidectomy allows use of thyroglobulin for recurrence monitoring and use of RAI for microscopic disease (MCQ)
      • Medullary Thyroid Cancer:
        • 20% of those with MTC have MEN II
        • 100% of those with MEN II have MTC
        • MEN II associated MTC tends to be  
          • bilateral, younger, worse prognosis(MCQ)
          • RETprotooncogene (MCQ)
          • Aggressiveness is  as follows:
            • MEN IIB [perform thyroidectomy by 6monthsold] > MEN IIA [perform thyroidectomy by 5yearsold] > FMTC (MCQ)
        • May see amyloid on pathology
        • serum calcitonin (can use serum calcitonin levels to monitor for recurrence) (MCQ)
        • Originates from parafollicular C cells, which produce calcitonin and hence do not concentrate iodine. (MCQ)
      • Anaplastic:
        • Only operation that should be considered is tracheostomy.
        • Minimal role for palliative resection
        • Medical management(MCQ)
          • Thyroid hormone suppression
          • Radioactive iodine ablation (RIA)
            • T3 [halflife 3 4 days] vs. T4 [halflife 4 weeks]
            • Hence use T3 replacement postop before RIA
      • Thyroglobulin can only serve as a tumor marker when the following 2 conditions are met: (MCQ)
        • The tumor is well differentiated(since it’s produced by follicular cells)
        • The patient has had a total thyroidectomy
      • Lymph nodes
        • For differentiated cancer: no role for prophylactic LND (MCQ)
        • only for palpable or FNA+ nodes —- “Regional dissection” (MCQ)
          • Radical dissection takes levels I – VI + jugular + CNXI
          • Modified Radical dissection
            • takes levels II – VII
            • spares IJV, SCM, spinal accessory nerve XI (MCQ)
        • Levels most at risk are II – VI
      • Prognosis (for well differentiated thyroid cancer):
        • Age
        • grade/mets
        • extent
        • size
        • TNM
      • However, age, grade (histology), size most important (MCQ)
      • Age (> 45, or < 14) is single greatest factor deciding prognosis (MCQ)
      • Superior laryngeal nerve (both sensory and motor) (MCQ)
        • External branch:
          • motor to cricothyroid
          • injury lose projection, high pitch tone
          • provides sensory to supraglottis
      • Recurrent laryngeal nerve:
        • innervates all of larynx except cricothyroid
        • bilateral injury causes airway occlusion
      • Always assess cord function before any operation on thyroid to document RLN function


thyroid cancer
Table of Contents:

00:03 – Medullary Papillary & Follicular Thyroid Carcinoma
00:21 – Thyroid Carcinomas
01:02 – Risk Factors
01:37 – Papillary Carcinoma
02:23 – Follicular
03:08 – Medullary Carcinoma
03:40 – Clinical Presentations
03:47 – Clinical Presentation
04:50 – Treatment
05:28 – Slide References
Thyroid Cancer: Adenoma, Papillary, Follicular, Medullary, Anaplastic for USMLE Step
Thyroid Cancers for USMLE Step 1:
In this video we will be looking at Adenoma Thyroid Cancer. Papillary Thyroid Cancer. Follicular Thyroid Cancer, Medullary Thyroid Cancer and finally anaplastic Thyroid Cancer. This will include the pathognesis of the thyroid cancers, histology of the thyroid cancers, symptoms of thyroid cancer, investigations and treatment of thyroid cancers as well as prognosis of thyroid cancers.

Histopathology Thyroid –Papillary carcinoma
Histopathology Thyroid –Papillary carcinoma
TCGA: Papillary Thyroid Carcinoma Analysis – Thomas Giordano
Endoscopic total thyroidectomy with node dissection for papillary thyroid cancer
This video demonstrates the technique of total thyroid excision with lymph node removal for papillary thyroid cancer.
Histopathology Thyroid–Follicular carcinomaHistopathology Thyroid–Follicular carcinoma
Thyroid carcinoma
This patient had a thyroid carcinoma which was removed surgically
Removal of Thyroid Tumor Part 1
Modern technique for the safe and precise removal of thyroid tumors.
Thyroid Surgery & Its Risks / Complications (Thyroidectomy) (GRAPHIC)
Video describes how a total thyroid removal is performed along with possible complications. Specifically discussed are recurrent laryngeal nerve damage causing permanent hoarseness as well as parathyroid gland damage leading to calcium regulation problems in the body
Removal of thyroid carcinoma in a dog using ligasure
Removal of a thyroid carcinoma in a dog using ligasure. Recurrent laryngeal nerve, carotid artery and vagosympathetic trunk are preserved.