Development of medullary thyroid carcinoma on a toxic nodule: about an exceptional case

We report the case of a 60-year-old hypertensive female patient who presented with an anterior neck swelling associated with local compression signs. TSH levels were in favor of hyperthyroidism. Cervical ultrasound showed two nodules classified as EU-TIRADS III, one of which, located at the lower right pole, was hyperfunctioning on I-123 scintigraphy. After total thyroidectomy, the histopathological study confirmed that the toxic nodule corresponded to a medullary thyroid carcinoma. Calcitonin levels were 115.6 ng/L (N < 10 ng/L). The staging workup, as well as the MEN screening, were unremarkable. An extensive lymph node dissection was performed, revealing no lymph node involvement.