Thyroid gland overview anatomy and physiology

The presentation from king fahd university
Which present the anatomy and physiology of the thyroid gland

1. THYROID GLANDTHYROID GLAND

2. MUST KNOWMUST KNOW
How to examine the neck and diagnose thyroid How to examine the neck and diagnose thyroid
enlargement from other neck lumps.enlargement from other neck lumps.
Clinical presentation of hypo and hyperClinical presentation of hypo and hyper
Meaning and interpretaion of thyroid function Meaning and interpretaion of thyroid function
tests.tests.
How to investigate and manage a patient with How to investigate and manage a patient with
STNSTN
Clinical features ,dx and management of thyroid Clinical features ,dx and management of thyroid
neoplasmsneoplasms

3. ANATOMY AND PHYSIOLOGYANATOMY AND PHYSIOLOGY
WHY DOES THE YHROID MOVE ON WHY DOES THE YHROID MOVE ON
SWALLOWING.SWALLOWING.

11. MIDLINE SWELLINGSMIDLINE SWELLINGS
Thyroid enlargementThyroid enlargement
Thyroglossal cystThyroglossal cyst
Dermoid cystDermoid cyst

12. HYPOTHYROIDISMHYPOTHYROIDISM
F:M 10:1F:M 10:1
Due to commonly hashimotos[TPO AND ANTI Due to commonly hashimotos[TPO AND ANTI
THYROGLOBULIN IS RAISED]THYROGLOBULIN IS RAISED]
Symptoms and signsSymptoms and signs
ExamExam
Lymphoma can develop on a back ground of Lymphoma can develop on a back ground of
autoimmune diseaseautoimmune disease
TSH,T4 ,T3TSH,T4 ,T3
TX ThyroxineTX Thyroxine

13. hyperthyroidismhyperthyroidism
Causes includeCauses include
Grave’sGrave’s
Toxic multinodular goiterToxic multinodular goiter
Solitary toxic adenomaSolitary toxic adenoma
Tx with thyroid uptake drugs Tx with thyroid uptake drugs
radioactive iodineradioactive iodine
surgery surgery

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

19. TSH : Low if toxic TSH : Low if toxic
FNAFNA
USUS
X-ray of thoracic inletX-ray of thoracic inlet
Tx – Total for non-toxic if there is Tx – Total for non-toxic if there is
retrosternal ext., trachael comp or retrosternal ext., trachael comp or
cosmotically unacceptable cosmotically unacceptable
If toxic - tx first the either total or If toxic - tx first the either total or
radioactive iodine radioactive iodine

23. SOLITARY THYROID NODULESOLITARY THYROID NODULE
5% Of female population. But only 5% are 5% Of female population. But only 5% are
malignant.malignant.
Causes 1- thyroid cystCauses 1- thyroid cyst
2- degenerative thyroid nodule2- degenerative thyroid nodule
3- benign follicular adenoma 3- benign follicular adenoma
4- differentiated thyroid ca4- differentiated thyroid ca

24. HistoryHistory
Feature suggestive of malignancy Feature suggestive of malignancy
1- previous irradiation (as a child)1- previous irradiation (as a child)
2- hoarsness2- hoarsness
3- family Hx (papillary)3- family Hx (papillary)

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

26. Isotope scan Increase uptake = hot Isotope scan Increase uptake = hot
Decreased uptake = coldDecreased uptake = cold
TreatmentTreatment

27. Thyroid tumoursThyroid tumours
Benign thyroid tumoursBenign thyroid tumours
Most are follicular adenomasMost are follicular adenomas
Papillary adenomas are rarePapillary adenomas are rare
All papillary tumours should be considered All papillary tumours should be considered
malignantmalignant

28. Follicular adenomaFollicular adenoma
Of all follicular lesions-80% benign and 20% Of all follicular lesions-80% benign and 20%
malignantmalignant
They are smooth and discrete lesions with They are smooth and discrete lesions with
glandular or acinar patternglandular or acinar pattern
They are incapsulated usually 2-4 cm in They are incapsulated usually 2-4 cm in
diameterdiameter
Adenomas can not be differentiated from Adenomas can not be differentiated from
carcinoma on FNA cytologycarcinoma on FNA cytology
Requires histological assessment of capsular Requires histological assessment of capsular
invasioninvasion

29. Malingnat thyroid tumoursMalingnat thyroid tumours
Differentiated thyroid cancer accounts for Differentiated thyroid cancer accounts for
80% of thyroid neoplasms80% of thyroid neoplasms
Female : Male ratio is 4:1Female : Male ratio is 4:1
Usually presents as solitary thyroid nodule Usually presents as solitary thyroid nodule
in young/middle age adultin young/middle age adult
Nodule more likely to be malignant in man Nodule more likely to be malignant in man
or childor child
Papillary and follicular tumours are Papillary and follicular tumours are
biologically very differentbiologically very different

30. Comparison of papillary and Comparison of papillary and
follicular tumoursfollicular tumours
Papillary tumours Follicular tumoursPapillary tumours Follicular tumours
Multifocal SolitaryMultifocal Solitary
Unencpasulated EncapsulatedUnencpasulated Encapsulated
Lymphatic spread Haematogenous spreadLymphatic spread Haematogenous spread
Metastasize to Metastasize to lung.Metastasize to Metastasize to lung.
regional bone and brainregional bone and brain

31. Papillary and mixed tumoursPapillary and mixed tumours
Accounts fro 70% Of Ca. thyroid.Accounts fro 70% Of Ca. thyroid.
20-40 yrs20-40 yrs
50% tumours are less than 2cm diameter 50% tumours are less than 2cm diameter
at presentationat presentation
Tumours less than 1cm diameter regarded Tumours less than 1cm diameter regarded
as minimal or micropapillary lesoinsas minimal or micropapillary lesoins
Psammoma bodies and “orphan Annie” Psammoma bodies and “orphan Annie”
nuclei are characteristic nuclei are characteristic
histologicalfeatureshistologicalfeatures

32. 30%-50% are multicentric with 30%-50% are multicentric with
simultaneous tumour in contralateral lobesimultaneous tumour in contralateral lobe
Early spread occurs to regional lymph Early spread occurs to regional lymph
nodesnodes
Thyroid lobectomy adequate for minimal Thyroid lobectomy adequate for minimal
lesionslesions
Total thyroidectomy is otherwise surgery Total thyroidectomy is otherwise surgery
of choiceof choice

33. Many tumours are TSH dependent Many tumours are TSH dependent
TSH suppression with post-operative TSH suppression with post-operative
thyroxine appropriatethyroxine appropriate
Thyroxine reduces recurrence and Thyroxine reduces recurrence and
improves survivalimproves survival
80% nodes have microscopic involvement80% nodes have microscopic involvement
Role of prophylactic lymph node dissection Role of prophylactic lymph node dissection
at time of initial surgery unclearat time of initial surgery unclear

34. Lymph node dissection does not improve Lymph node dissection does not improve
survivalsurvival
Alternative is to sample the lymph nodesAlternative is to sample the lymph nodes
If negative-no further surgeryIf negative-no further surgery
If positive-modified neck dissectionIf positive-modified neck dissection
Prognosis excellent (90% 20 yrs)Prognosis excellent (90% 20 yrs)

35. Follicular tumoursFollicular tumours
40 – 50 yrs40 – 50 yrs
Can not differentiate follicular adenoma and carcinoma Can not differentiate follicular adenoma and carcinoma
on FNA cytologyon FNA cytology
Treatment of all follicular neoplasms is thyriod lobectomy Treatment of all follicular neoplasms is thyriod lobectomy
with frozen sectionwith frozen section
If frozen section confirms carcinoma- total thyriodectomyIf frozen section confirms carcinoma- total thyriodectomy
If frozen section confirms adenoma-No further surgery If frozen section confirms adenoma-No further surgery
requiredrequired
Total thyroidectomy allows detection of metastased Total thyroidectomy allows detection of metastased
using 123/Scanning during follow upusing 123/Scanning during follow up
All patients require suppressive thyroxine therapy All patients require suppressive thyroxine therapy

36. Follow up of thyroid carcinomaFollow up of thyroid carcinoma
Annual isotope scanning to detect Annual isotope scanning to detect
asymptomatic recurrenceasymptomatic recurrence
Treatment of such recurrence can still be Treatment of such recurrence can still be
curativecurative
Serum thyroglobulin-increasing levels Serum thyroglobulin-increasing levels
often first sign of recurrence often first sign of recurrence

37. Anaplastic carcinomaAnaplastic carcinoma
Accounts for less than 5%thyroid malignancies Accounts for less than 5%thyroid malignancies
Occurs in elderly and is usually an aggressive Occurs in elderly and is usually an aggressive
tumourtumour
Local infilteration causes dysponea and Local infilteration causes dysponea and
dysphagiadysphagia
Thyriodectomy seldom feasibleThyriodectomy seldom feasible
incision biopsy should be avoided as it often incision biopsy should be avoided as it often
causes uncontrollable local spreadcauses uncontrollable local spread
Radiotherapy and chemotherapy important Radiotherapy and chemotherapy important
modes of treatmentmodes of treatment
Death usually occurs within 6 months Death usually occurs within 6 months

38. Thyroid lymphomaThyroid lymphoma
Accounts for 2% of thyroid malignancies Accounts for 2% of thyroid malignancies
Often arises with Hashimotos thyroiditis or non-Often arises with Hashimotos thyroiditis or non-
Hodgkins B-cell lymphomaHodgkins B-cell lymphoma
Presents as a goitre in association with Presents as a goitre in association with
generalized lymphomageneralized lymphoma
Diagnosis can often be made by FNA cytologyDiagnosis can often be made by FNA cytology
Radiotherapy is treatment of choice Radiotherapy is treatment of choice
Prognosis is good – often more than 85% 5 yr Prognosis is good – often more than 85% 5 yr
survivalsurvival

39. Medullary carcinomaMedullary carcinoma
8% 8%
Para-follicular C-cellsPara-follicular C-cells
20% are familial20% are familial
Can occur as part of MEN 2Can occur as part of MEN 2
80% of cases are sporadic 80% of cases are sporadic
Sporadic cases usually unilateralSporadic cases usually unilateral
50% have lymph nodes at presentation50% have lymph nodes at presentation
Familial cases often multifocal and bilateralFamilial cases often multifocal and bilateral
Tumours mets to nodes and via blood to bone, liver and lungTumours mets to nodes and via blood to bone, liver and lung
They produce calcitonin,They produce calcitonin,
Total thyroidectomy is treatment of choiceTotal thyroidectomy is treatment of choice
Calcitonin can be used in follow up for the presence of metastatic Calcitonin can be used in follow up for the presence of metastatic
diseasedisease

40. THANK YOUTHANK YOU