<prompt> A 26-years women presents with a palpable thyroid nodule, and needle biopsy demonstrates amyloid in the stroma of the lesion. A cervical lymph node is palpable on the same side as the lesion. The preferred treatment should be:Removal of the involved node, the isthmus, a poion of the opposite bone and he enlarged lymph nodeRemoval of the involved lobe, the isthmus, a poion of the opposite lobe, and he enlarged lymph nodeTotal thyroidectomy and modified neck dissection on the side of the enlarged lymph nodeTotal thyroidectomy and irradiation of the cervical lymph nodes  <response>: MEDULLARY CARCINOMA THYROID Neuroendocrine carcinoma arising from parafollicular ;C; cells of thryoid Parafollicular ;C; cells are derived from the ultimobranchial bodies secrete calcitonin ;C; cells are concentrated superolaterally in throid lobes, from where MTC usually develops. Most MTCs 75-80 arise sporadically Spread is both lymphatic hematogenous MC site of metastasis Liver. Clinical features High level of serum Calcitonin CEA Cervical lymph nodes at the time of presentation LN involvement, thyroid and blood borne metastases occurs early Diarrhoea at the time of presentation Amyloid in stroma histologically MEN setting: Evidence of PheochromocytomaHyperparathyroidismThyroid cancer in Family Discovery of medullary carcinoma thyroid makes family surveillance advisable Diagnosis Diagnosed by FNAC I131 scan is of no use as MTC is TSH independent Tumor marker: Calcitonin is raised in almost all cases of MTC Calcitonin excess in MTC is not associated with hypocalcemia. Treatments : Total Thyroidectomy Central LN dissection- Ipsilateral MRND if tumor 1 cm If nodes are positive on ipsilateral side: Bilateral MRND Follow-Up: Level of calcitonin falls after resection and is raises again in cases of recurrence, used for follow-up Prognosis: MTC is associated with poor prognosis Ref: Sabiston 20th edition Pgno: 909 