A 35-year-old woman presents with a thyroid nodule. Fine needle aspiration shows cells positive for calcitonin immunostaining. Serum calcitonin is markedly elevated. Calcitonin is a specific tumor marker for which thyroid carcinoma?

• A Papillary carcinoma
• B Follicular carcinoma
• C Anaplastic carcinoma
• D Medullary carcinoma ✓

Explanation

Medullary thyroid carcinoma arises from parafollicular D cells, which normally produce calcitonin. Elevated serum calcitonin is a highly specific tumor marker for this cancer. Papillary carcinoma is associated with thyroglobulin and BRAF mutations. Follicular carcinoma also uses thyroglobulin. Anaplastic carcinoma is an aggressive undifferentiated tumor without a specific hormonal marker.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.