3Malignant Papillary Carcinoma Follicular Carcinoma Medullary Carcinoma Anaplastic and poorly differentiated carcinomaPrimary lymphoma of the thyroidMetastatic carcinoma
4Clinical features Most thyroid nodules are asymptomatic Nodules that produce thyroid hormones in excess-palpitation-anxiety-clammy skin-increased appetite-weight loss-heat intoleranceNodules can press adjacent structures in neck causing-hoarseness of voice(recurrent laryngeal N compression)-dysphagia-dyspnoea-pain in neck
5Nodules sometimes found in hashimoto’s thyroiditis, which may cause symptoms of an underactive thyroid gland-dry skin-face swelling-intolerance to cold-weight gain-decreased appetite-hair loss
7Ultrasonography Most sensitive test to detect lesions in the thyroid Indicated in all patients who have a nodular thyroid, with a palpable solitary nodule or a multinodular goiter,be evaluated by USNot as screening test in general population
8USG findings Number Size Extracapsular growth Cystic lesions Cervical LN
9Findings suggestive of malignancy: –Presence of halo –Irregular border –Presence of cystic components –Presence of calcifications –Heterogeneous echo pattern –Extrathyroidal extension
10Radionuclide Scanning Used to identify whether a nodule is functioning or not.Functioning nodules are nearly always benignApproximately 90 percent of nodules are nonfunctioning5 percent of nonfunctioning nodules are malignantHowever even with suppressed level of serum TSH patient can have both functioning and non functioning nodules.Thus, even suppressed level of serum TSH may obviate the need for biopsy.
11Usually either Technetium(Tc99) or Radioiodine(I123) used. Normal follicular cells will trap both but only radioiodine is added to tyrosine and stored in the colloid spaceBoth benign and almost all malignant neoplastic tissue concentrate both radioisotopes less than normal thyroid tissueIn most centers, the routine initial diagnostic evaluation of a solitary thyroid nodule no longer includes imaging studies.In the past, radionuclide scanning was an important imaging study performed routinely in the initial assessment of a thyroid nodule.
12Cold Nodules Cyst Non-functioning Adenoma Malignancy however, 5-8% of warm or cold nodules are malignant.
16Limitations of Thyroid scan Two dimensional scanning techniqueInability to measure the size of a nodule accuratelyMissed malignant thyroid nodulesSuperimposition of abnormal nodular tissue and normally functional thyroid tissue can give impression of normally functioning tissueIt is estimated that only half of malignant thyroid nodules present as cold defects
17Other imaging tech CT and MRI not as routine. Can asses size, retrosternal extension, position and relation to the surrounding structure.
18Images of a large, asymmetric multinodular goiter Images of a large, asymmetric multinodular goiter. (A) Chest radiography shows marked tracheal deviation to the right (arrow). (B) Chest CT confirmed the presence of a large substernal goiter on the left to the level of tracheal bifurcation.
19USG guided FNAC Indicated if: Palpation-guided FNAC non-diagnosticComplex (solid/cystic) nodulePalpable small nodule (<1.5 cm)Impalpable noduleAbnormal cervical nodesNodule with suspicious US featuresFNAC results are:70% Benign, 10% Malignant or suspicious of malignancy, and 20% Unsatisfactory
22Suspicious cytology in FNAC Diagnosis cannot be madeInculdes:Follicular neoplasms,Atypical PTC, orLymphoma
23FNAC LimitationsThe absence of malignant cells in an acellular or hypocellular specimen does not exclude malignancyInability to reliably distinguish a benign follicular adenoma from a follicular malignant tumour
24TSH TPOAb To detect early or subtle thyroid dysfunction. If TSH levels abnormal, free T3 & T4 should be measured to confirm the diagnosisTPOAbThyroid peroxidase antibodyThough characteristically observed in hypothyroidism, can also be seen in patients of hyperthyroidism and subacute thyroiditisHypothyroid (inc TSH) in hashimoto…. Hyperthyroid (dec THS) in subacute
25Serum Tg Serum Calcitonin Correlates with iodine intake and the size of the thyroid gland rather than with the nature or function of the noduleSeldom used in nodule diagnosis Extremely elevated levels of Tg may suggest thyroid metastasis.Serum CalcitoninGood marker for medullary carcinoma and correlates well with tumor burden