The variation of cells in size is a normal finding in all hormonally active organs. The presence of anisonucleosis (i.e. the variation in size in excess of normal value) has a very limited diagnostic value in thyroid cytology, and has practically no relevance in the case of Hashimoto's thyroiditis. Both the thyroiditis itself and the hormonal changes caused by thyroiditis may cause this type of atypia.

The examples presented here are more interesting because of oxyphilic cell proliferation. Nevertheless, we found lymphocytes within cell groups formed by follicular cells. Therefore, this pattern should not cause any problem for an experienced cytopathologist.