THYROID GLAND

1. THYROID GLAND

2. 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

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

11. MIDLINE SWELLINGS • Thyroid enlargement • Thyroglossal cyst • Dermoid cyst

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

13. hyperthyroidism • Causes include • Grave’s • Toxic multinodular goiter • Solitary toxic adenoma • Tx with thyroid uptake drugs • radioactive iodine • surgery

14. 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%.

19. 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

23. 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

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

25. 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)

26. Isotope scan Increase uptake = hot Decreased uptake = cold • Treatment

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

28. 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

29. Malingnat thyroid tumours • Differentiated thyroid cancer accounts for 80% of thyroid neoplasms • Female : Male ratio is 4:1 • 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

30. 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

31. 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

32. 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

33. 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

34. 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)

35. 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

36. 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

37. Anaplastic carcinoma • Accounts for less than 5%thyroid 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

38. 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

39. 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

40. THANK YOU