Concurrent medullary and papillary carcinoma of thyroid.

Simultaneous occurrence of papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma (MTC) in the same thyroid gland is a rare condition. These tumors derive from different cells; PTC originates from follicular cells whereas MTC originates from parafollicular cells. Because of this, the treatment of these tumors also differs. This article describes two rare cases of the simultaneous occurrence of MTC and PTC in the thyroid gland.