In which carcinoma of thyroid treatment with 1-131 is most helpful?

Ans. b (Follicular). (Ref. Bailey and Love, 25th/797; Harrison's Medicine 16th/pg.2125)There are 4 main types of thyroid carcinoma:# Papillary carcinoma (lymphadenopathy and lateral aberrant thyroid, psammoma bodies & Orphan Annie eyed nuclei)# Follicular and hurthle cell carcinoma (May develop in patients with multinodular goitre, blood borne metastasis, bone secondaries most common in Hurthle cell variety, radioactive iodine may be useful in treatment). Hurthle cell tumours are a variant of follicular neoplasm in which oxyphil (Hurthle, Askanazy) cells predominate histologically and it carries poor prognosis.# Medullary carcinoma (may be associated with MEN 2A and 2B and amyloidosis)# Anaplastic carcinoma (worst prognosis): Local infiltration is an early feature of these tumours, with spread by lymphatics and by the bloodstream. They are extremely lethal tumours. Some of these aggressive lesions present in an advanced stage with tracheal obstruction and they require urgent tracheal decompression. The trachea may be decompressed and tissue obtained for histology by isthrnusectomy. Tracheostomy is best avoided. Radiotherapy should be given in all cases and may provide a worthwhile period of palliation.- B-cell lymphoma of thyroid may be predisposed by hashimoto's thyroiditis# Most patients with stage 1 PTC (Papillary thyroid cancer) with primary tumors < 1.5 cm in size can be managed safely with thyroxine suppression, without radiation treatment, as the risk of recurrence and mortality is very low.# For patients with FTC (follicular thyroid cancer), larger PTCs, spread to the adjacent lymph nodes, or evidence of metastases, thyroid ablation and radioiodine treatment are generally indicated.