A Benign Medullary Thyroid Cancer

Metastatic dissemination occurs in up to 90% of patients with medullary thyroid cancer (MTC) greater than 4 cm in diameter, and elevated calcitonin levels of more than 500 pg/ml preoperatively have been shown to predict the failure to achieve biochemical remission. Herein, we present a patient with a large tumor and extremely elevated calcitonin level, who was subsequently found to show a “benign” behavior with no evidence of metastasis. The relatively benign behavior of this patient's MTC despite its size and extremely elevated calcitonin levels is thought to be suggestive of certain mutation types in MTC to be more associated with better prognostic outcomes. This case report highlights the value of genetic studies on disease prognostication and the need for comprehensive research studies on genomic profiling in MTC to better understand the relationship of different mutations with prognosis and outcome.