[Diagnosis of differentiated thyroid cancers]

Thyroid nodule is a frequent clinical problem. Since the majority of these are benign, it is important to identify the cancers among them and at the same time avoid surgery in most. Fine needle aspiration biopsy is a direct method, reliable and without risk. Today this technique constitute the first step in evaluation of a thyroid nodule. If done properly, it will have a false negative rate of 1 to 2%. In few cases the diagnosis will remain uncertain even after the needle biopsy. In these cases thyroid scan and clinical criteria will be helpful to reach a therapeutic decision.