Medullary carcinoma of Thyroid is characterized by all, except -

Medullary carcinoma thyroid Accounts for approximately 7% of malignant tumour of the thyroid. It arises from ultimobranchial bodies (from the parafollicular C cells derived from neural crest and not from thyroid follicles). It contains amyloid stroma Familial medullary carcinoma occurs in 25% of patients (Marfanoid habitus, Amyloidosis and Hirschsprung's disease also occur in patients with familial medullary cancer). Medullary carcinoma occurs in association with (MEN) syndrome. All patients with medullary carcinoma of thyroid should be screened for RET point mutation on chromosome 10. Medullary Ca thyroid secretes calcitonin, this cause hypocalcemia. Calcitonin also acts as tumour marker. Involvement of the lymph node is very common in medullary carcinoma. It is seen in 50-60% of cases.