THYROID GLAND

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THYROID GLAND
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MUST KNOW

• How to examine the neck and diagnose thyroid
  enlargement from other neck lumps.
• Clinical presentation of hypo and hyper
• Meaning and interpretaion of thyroid function
  tests.
• How to investigate and manage a patient with STN
• Clinical features ,dx and management of thyroid
  neoplasms

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ANATOMY AND PHYSIOLOGY

• WHY DOES THE YHROID MOVE ON SWALLOWING.

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MIDLINE SWELLINGS

• Thyroid enlargement
• Thyroglossal cyst
• Dermoid cyst

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HYPOTHYROIDISM

• FM 101
• Due to commonly hashimotosTPO AND ANTI
  THYROGLOBULIN IS RAISED
• Symptoms and signs
• Exam
• Lymphoma can develop on a back ground of
  autoimmune disease
• TSH,T4 ,T3
• TX Thyroxine

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hyperthyroidism

• Causes include
• Graves
• Toxic multinodular goiter
• Solitary toxic adenoma
• Tx with thyroid uptake drugs
• radioactive iodine
• surgery
  
  

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MNG

• Majority are non toxic
• Some can become toxic ( plummers disease)
• May extend retrosternally if large causing
  trachael deviation, compression and strider
• O/E multinodular if there is dominant nodule then
  this should be investigated as the risk of
  malignancy in this nodule is about 10.

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• TSH Low if toxic
• FNA
• US
• X-ray of thoracic inlet
• Tx Total for non-toxic if there is retrosternal
  ext., trachael comp or cosmotically unacceptable
• If toxic - tx first the either total or
  radioactive iodine

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SOLITARY THYROID NODULE

• 5 Of female population. But only 5 are
  malignant.
• Causes 1- thyroid cyst
• 2- degenerative thyroid nodule
• 3- benign follicular adenoma
• 4- differentiated thyroid ca

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• History
• Feature suggestive of malignancy
• 1- previous irradiation (as a
  child)
• 2- hoarsness
• 3- family Hx (papillary)

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• Investigation
• Exclude solitary toxic adenoma (where TSH is
  suppressed) malignancy therefore TSH and FNA
  most important
• If suspicious on FNA then for surgery as 30 are
  malignant
• Ultrasound to distinguish solid from cystic or
  dominant nodule within MNG (50 STN)

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• Isotope scan Increase uptake hot
• Decreased uptake cold
• Treatment

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Thyroid tumours

• Benign thyroid tumours
• Most are follicular adenomas
• Papillary adenomas are rare
• All papillary tumours should be considered
  malignant

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Follicular adenoma

• Of all follicular lesions-80 benign and 20
  malignant
• They are smooth and discrete lesions with
  glandular or acinar pattern
• They are incapsulated usually 2-4 cm in diameter
• Adenomas can not be differentiated from carcinoma
  on FNA cytology
• Requires histological assessment of capsular
  invasion

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Malingnat thyroid tumours

• Differentiated thyroid cancer accounts for 80 of
  thyroid neoplasms
• Female Male ratio is 41
• Usually presents as solitary thyroid nodule in
  young/middle age adult
• Nodule more likely to be malignant in man or
  child
• Papillary and follicular tumours are biologically
  very different

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Comparison of papillary and follicular tumours

• Papillary tumours Follicular tumours
• Multifocal Solitary
• Unencpasulated Encapsulated
• Lymphatic spread Haematogenous spread
• Metastasize to Metastasize to lung.
• regional bone and brain

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Papillary and mixed tumours

• Accounts fro 70 Of Ca. thyroid.
• 20-40 yrs
• 50 tumours are less than 2cm diameter at
  presentation
• Tumours less than 1cm diameter regarded as
  minimal or micropapillary lesoins
• Psammoma bodies and orphan Annie nuclei are
  characteristic histologicalfeatures

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• 30-50 are multicentric with simultaneous tumour
  in contralateral lobe
• Early spread occurs to regional lymph nodes
• Thyroid lobectomy adequate for minimal lesions
• Total thyroidectomy is otherwise surgery of
  choice

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• Many tumours are TSH dependent
• TSH suppression with post-operative thyroxine
  appropriate
• Thyroxine reduces recurrence and improves
  survival
• 80 nodes have microscopic involvement
• Role of prophylactic lymph node dissection at
  time of initial surgery unclear

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• Lymph node dissection does not improve survival
• Alternative is to sample the lymph nodes
• If negative-no further surgery
• If positive-modified neck dissection
• Prognosis excellent (90 20 yrs)

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Follicular tumours

• 40 50 yrs
• Can not differentiate follicular adenoma and
  carcinoma on FNA cytology
• Treatment of all follicular neoplasms is thyriod
  lobectomy with frozen section
• If frozen section confirms carcinoma- total
  thyriodectomy
• If frozen section confirms adenoma-No further
  surgery required
• Total thyroidectomy allows detection of
  metastased using 123/Scanning during follow up
• All patients require suppressive thyroxine
  therapy

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• Follow up of thyroid carcinoma
• Annual isotope scanning to detect asymptomatic
  recurrence
• Treatment of such recurrence can still be
  curative
• Serum thyroglobulin-increasing levels often first
  sign of recurrence

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Anaplastic carcinoma

• Accounts for less than 5thyroid malignancies
• Occurs in elderly and is usually an aggressive
  tumour
• Local infilteration causes dysponea and dysphagia
• Thyriodectomy seldom feasible
• incision biopsy should be avoided as it often
  causes uncontrollable local spread
• Radiotherapy and chemotherapy important modes of
  treatment
• Death usually occurs within 6 months

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Thyroid lymphoma

• Accounts for 2 of thyroid malignancies
• Often arises with Hashimotos thyroiditis or
  non-Hodgkins B-cell lymphoma
• Presents as a goitre in association with
  generalized lymphoma
• Diagnosis can often be made by FNA cytology
• Radiotherapy is treatment of choice
• Prognosis is good often more than 85 5 yr
  survival

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Medullary carcinoma

• 8
• Para-follicular C-cells
• 20 are familial
• Can occur as part of MEN 2
• 80 of cases are sporadic
• Sporadic cases usually unilateral
• 50 have lymph nodes at presentation
• Familial cases often multifocal and bilateral
• Tumours mets to nodes and via blood to bone,
  liver and lung
• They produce calcitonin,
• Total thyroidectomy is treatment of choice
• Calcitonin can be used in follow up for the
  presence of metastatic disease

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THANK YOU