AgNOR staining < 100 intact cells for investigation
Ultrasonography Cystic component > 5% at any time
  Nodule in direct contact with an adjacent nodule
Scintigraphy Autonomously functioning nodule in the thyroid at initial investigation
Laboratory TSH > 4 mU/L at any time
  TSH < 0.2 mU/L at any time
  aTPO> 100 U/L
Medication Thyrostatic and/or thyroid hormone and/or iodine containing drug at any time
Cytology Suspicious or malignant and not operated on
  Lymphocytic thyroiditis
Histology Malignant or diffuse lymphocyticthyroiditis
Follow-up period < 10.years in non-operated patients
  <6 years in operated patients
Table 1: Exclusion criteria.