Endocrine Abstracts

MTC represents still a diagnostic challenge in thyroidology. A case is here reported with some misleading signs that was finally solved with a calcitonin assay.

A 50 years women was referred for a thyroid nodule incidentally discovered at echography in the right lobe; it appeared round, hypoechoic, without alo sign, well-definite edges, with a diameter of 7 mm. At the first evaluation with echocolordoppler there was no appearance of intralesion vascularization. TSH was 0.19, thyroid antibodies were absent. A Tc99 scintiscan demonstrated an iso-uptake area in correspondence of nodule. The subject was put in ultrasound follow-up: a size evolution to 12 mm was shown, while ECD demonstrated an appearance of intra lesion color sign. A citology showed a follicular pattern. At this time a calcitonin assay was done that demonstrated high levels; she was referred to surgery. MTC emerged in the nodule.

Some considerations arise about this case: A) the initial signs were confounding because the presence of low TSH with not clear scintiscan suggesting the possibility of pre autonomous thyroid nodule;and indeterminate result of citology and ECD; C) for this kind of small nodule, even if a cytology is not indicated, an accurate follow-up with ultrasound is recommended, to arise the diagnostic doubt about the nature of the nodule; D) the solution of the diagnostic challenge derived by an intuition of an assay of calcitonin, owing to growing even if minimal, of nodule size.

Once again the importance of calcitonin assay is demonstrated. If screening is no acceptable for cost benefits, this test has to be well present in our mind, both at starting nodule work-up if doubts emerged from ultrasound, ECD,cytology point of view and,like in our case, along the course of echography follow-up, that is advised in guidelines for small nodule less than 1 cm.