THYROID GLANDTHYROID GLAND

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

ANATOMY AND PHYSIOLOGYANATOMY AND PHYSIOLOGY

WHY DOES THE YHROID MOVE ON WHY DOES THE YHROID MOVE ON SWALLOWING.SWALLOWING.

MIDLINE SWELLINGSMIDLINE SWELLINGS

Thyroid enlargementThyroid enlargement

Thyroglossal cystThyroglossal cyst

Dermoid cystDermoid cyst

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

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

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%.

TSH : Low if toxic TSH : Low if toxic FNAFNAUSUSX-ray of thoracic inletX-ray of thoracic inletTx – 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

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

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)

InvestigationInvestigationExclude 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)

Isotope scan Increase uptake = hot Isotope scan Increase uptake = hot

Decreased uptake = coldDecreased uptake = cold

TreatmentTreatment

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

Follicular adenomaFollicular adenoma

Of all follicular lesions-80% benign and 20% Of all follicular lesions-80% benign and 20% malignantmalignantThey are smooth and discrete lesions with They are smooth and discrete lesions with glandular or acinar patternglandular or acinar patternThey are incapsulated usually 2-4 cm in They are incapsulated usually 2-4 cm in diameterdiameterAdenomas can not be differentiated from Adenomas can not be differentiated from carcinoma on FNA cytologycarcinoma on FNA cytologyRequires histological assessment of capsular Requires histological assessment of capsular invasioninvasion

Malingnat thyroid tumoursMalingnat thyroid tumours

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

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

Papillary and mixed tumoursPapillary and mixed tumours

Accounts fro 70% Of Ca. thyroid.Accounts fro 70% Of Ca. thyroid.20-40 yrs20-40 yrs50% tumours are less than 2cm diameter 50% tumours are less than 2cm diameter at presentationat presentationTumours less than 1cm diameter regarded Tumours less than 1cm diameter regarded as minimal or micropapillary lesoinsas minimal or micropapillary lesoinsPsammoma bodies and “orphan Annie” Psammoma bodies and “orphan Annie” nuclei are characteristic nuclei are characteristic histologicalfeatureshistologicalfeatures

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

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

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)

Follicular tumoursFollicular tumours

40 – 50 yrs40 – 50 yrsCan not differentiate follicular adenoma and carcinoma Can not differentiate follicular adenoma and carcinoma on FNA cytologyon FNA cytologyTreatment of all follicular neoplasms is thyriod lobectomy Treatment of all follicular neoplasms is thyriod lobectomy with frozen sectionwith frozen sectionIf frozen section confirms carcinoma- total thyriodectomyIf frozen section confirms carcinoma- total thyriodectomyIf frozen section confirms adenoma-No further surgery If frozen section confirms adenoma-No further surgery requiredrequiredTotal thyroidectomy allows detection of metastased Total thyroidectomy allows detection of metastased using 123/Scanning during follow upusing 123/Scanning during follow upAll patients require suppressive thyroxine therapy All patients require suppressive thyroxine therapy

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

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 tumourtumourLocal infilteration causes dysponea and Local infilteration causes dysponea and dysphagiadysphagiaThyriodectomy seldom feasibleThyriodectomy seldom feasibleincision biopsy should be avoided as it often incision biopsy should be avoided as it often causes uncontrollable local spreadcauses uncontrollable local spreadRadiotherapy and chemotherapy important Radiotherapy and chemotherapy important modes of treatmentmodes of treatmentDeath usually occurs within 6 months Death usually occurs within 6 months

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

Medullary carcinomaMedullary carcinoma

8% 8% Para-follicular C-cellsPara-follicular C-cells20% are familial20% are familialCan occur as part of MEN 2Can occur as part of MEN 280% of cases are sporadic 80% of cases are sporadic Sporadic cases usually unilateralSporadic cases usually unilateral50% have lymph nodes at presentation50% have lymph nodes at presentationFamilial cases often multifocal and bilateralFamilial cases often multifocal and bilateralTumours mets to nodes and via blood to bone, liver and lungTumours mets to nodes and via blood to bone, liver and lungThey produce calcitonin,They produce calcitonin,Total thyroidectomy is treatment of choiceTotal thyroidectomy is treatment of choiceCalcitonin can be used in follow up for the presence of metastatic Calcitonin can be used in follow up for the presence of metastatic diseasedisease

THANK YOUTHANK YOU