A 20-year-old woman complains of rapid enlargement of her thyroid gland over the last six months. There is no history of fever, weight loss, dysphagia, hoarseness, or ocular problems. Her medical and surgical histories are unremarkable, although her family history is significant for medullary thyroid cancer diagnosed in her 48-year-old mother just 2 weeks ago. She only drinks socially and has never smoked. A complete blood count and thyroid function tests are within normal parameters.
The ultrasound scan shows a solitary hypoechogenic nodule measuring 2 x 3 cm, with multiple microcalcifications. The parathyroid glands appear normal, and there is no evidence of involvement of the regional lymph nodes or mediastinum. Cytology of the aspirate shows nests of eosinophilic polyhedral cells with peripheral palisading in a fibrovascular stroma, with a positive immunohistochemical test for calcitonin.
Serum calcitonin: 310ng/L (<10)
Metanephrine: 0.71 mg/24hr (<1.3) Normetanephrine: 26 mcg/24hr (15-80)
The CT is negative for loco-regional spread, and for distant metastases to the lungs or liver. Both adrenal glands appear to be normal.