A 32-year-old woman has a firm anterior neck mass with recent-onset diarrhoea. Serum calcium is 10.9 mg/dL, phosphate 2.6 mg/dL, and basal calcitonin is 1400 pg/mL. Fine-needle aspiration shows sheets of spindle-shaped cells with stromal amyloid that stains with Congo red. Which of the following is the most appropriate next step in management?
- A Radioactive iodine ablation of the nodule
- B Total thyroidectomy with central lymph node dissection, after screening for germline RET mutation ✓
- C Suppressive levothyroxine therapy with repeat ultrasound in six months
- D Somatostatin analogue therapy as definitive treatment
Correct answer: B. Total thyroidectomy with central lymph node dissection, after screening for germline RET mutation
Explanation
Calcitonin elevation, secretory diarrhoea, amyloid-rich cytology, and Congo red staining establish medullary thyroid carcinoma, arising from parafollicular C cells. About 25 percent of cases are hereditary (RET germline mutations), so genetic testing is mandatory before or alongside surgery. Total thyroidectomy with central compartment node dissection is curative intent treatment. C cells do not concentrate iodine, so radioactive iodine and suppressive thyroxine are ineffective, and somatostatin analogues are reserved for metastatic disease.
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.