Pathology Of Thyroid fsm.ac.fj

"The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy." – Martin Luther King Jr. Pathology of Thyroid Dr. Venkatesh M. Shashidhar Senior Lecturer in Pathology Fiji School of Medicine Normal Thyroid Gland Thyroid - Normal Normal resting Thyroid Thyroid Physiology: Hypothalamus TRH T3, T4 Pituitary TSH Thyroid Disorders of Thyroid:   Hyperthyroidism Hypothyroidism (Euthyroid)     Thyroiditis Diffuse multinodular Goiter. Neoplasms – adenoma/carcinoma. Congenital – Thyroglossal cyst/duct. Hyperthyroidism        Thyrotoxicosis – High T3/T4, low TSH Diffuse toxic hyperplasia (Graves) Toxic multinodular goitre Toxic adenoma Thyroiditis Functioning thyroid carcinoma TSH secreting pituitary adenoma Graves Disease:    Common (2%F) Females, 20-40y, Autoimmune. Triad of clinical features, • Hyperthyroidism • exopthalmos • Pretibial myxedema.    Ab to TSH receptor – LATS. Diffuse hyperplasia, tall columnar cells, papillary folds. Scalloped, pale, scanty colloid. Hyperthyroidism Features: Graves’ Thyroiditis: Graves Disease Hypothyroidism        Cretinism / Myxedema – Low T3/T4, High TSH Causes: Hashimoto’s thyroiditis - autoimmune Iodine deficiency Drugs – PAS, iodides, lithium Developmental – Atrophy, hypoplasia Pituitary disorders Radiation/Surgery Hypothyroidism        ‘Cretin’ism (child) Impaired cns & bone growth Mental retardation Short stature Coarse facial features Protruding tongue Umbilical hernia        Myxedema (adult) Slow physical and mental activity Cold intolerance Over weight Low cardiac output Constipation and decreased sweating Cool pale thick skin Hypothyroidism Myxedema Features: Thyroid Atrophy Hashimoto Thyroiditis          Common non endemic goitre. females more common 45-65y. Autoimmune HLA-DR5, DR3. Antithyroglobulin antibody Firm diffuse goitre. Follicle atrophy with lymphocytes. Hürthle cells – eosinophilic ep. cells. Initial hyperthyroidism. High risk of B cell lymphoma. Hashimoto’s Thyroiditis: Hashimoto’s Disease Hashimoto’s Disease Antithyroglobulin Antibody Antimicrosomal Autoantibody Granulomatous Thyroiditis:         Subacute or DeQuervain thyroiditis. Less common, Females, 30-60 years Pain, fever, fatigue, myalgia. Post viral syndrome. Genetic association - HLA B35 Patchy microabscess, granulomas with giant cells. Hyperthyroidism. Heals with normal thyroid function. DeQuervain's Disease - SAGT Diffuse Multinodular goitre         Endemic & sporadic types Cassava – thiocyanate – iodide transport. Sporadic – rare, females, young. Hyperplastic stage & Colloid stage. Repeated attacks  multinodular. Hyperplasia, fibrosis, cystic, necrosis Mass effect, dysphagia, airway obstruction Rarely toxic hyperthyroidism plummer syndrome. Goitre – Iodine Deficiency Multinodular Goitre with Papillary Carcinoma Colloid Cysts in MNG Multinodular Goitre Neoplasms of Thyroid     Usually solitary, benign. Good prognosis - <1% cancer mort. May be functional – hot nodule. Malignancy - Infiltration – fixation, hoarseness, recurrent laryngeal nerve damage. Neoplasms of Thyroid      Adenoma – Follicular adenoma - hot Papillary Carcinoma – 75-80% Follicular carcinoma - 10-20% Medullary carcinoma – 5% Anaplastic carcinoma - <5% Adenoma       Follicular common, rarely Papillary Compact follicles (large in MNG) Solitary, rarely Functional or hot. Centre may show necrosis/hem. Well capsulated. Compressed normal gland. Follicular Adenoma Follicular Adenoma Solitary Adenoma Follicular Adenoma Thyroid Carcinoma    Uncommon – child – elderly. Common - Papillary adenocarcinoma. Associated with radiation exposure. Thyroid Carcinoma Type Papillary Follicular % Age Spread Prognosis 65 Young <45y Lymph Excellent 20 Middle age B.V. Local All Good Poor variable Anaplastic 10 elderly Medullary 5 Elderly familial Papillary Carcinoma  Most common cancer – 75-80% • Idiopathic, Radiation, Gardner & Cowden syndromes. • Papillary folds, Psammoma bodies, Orphan-anne nucleus. • 98% 10year survival when localized. Papillary Carcinoma Papillary Carcinoma Medullary Carcinoma Amyloid in Medullary Carcinoma – Polarised microscopy Papillary Carcinoma Anaplastic Carcinoma Normal Technetium Scan Hot nodules Cold nodule Ultrasound Scan Solid nodule: Conclusions:  Hyperthyroidism • Graves, thyrotoxicosis, LATS. • Hypermetabolism, high T3/T4, low TSH  Thyrotoxicosis: • Antithyroglobulin, anti microsomal • Hypometabolism, Low T3/T4, high TSH.   Multinodular goitre – low iodine. Neoplasms • Follicular adenoma – capsulated, single. • Carcinoma: Papillary follicular, medullary, anaplastic. "To be conscious that you are ignorant of some facts is a great step in knowledge." – Benjamin Disraeli