The two cases differ in the cellular arrangement, the cells in the hyperplastic nodule presents less tendency to dissociate compared with the adenoma. Therefore the likelihood of being the right case an oxyphilic tumor is clearly higher than that of the left case. There was another, unusual sign in the latter, i.e. the cytoplasmic vacuolization. Nevertheless, the possibility of a Hürthle-cell tumor is relatively high even in the left case.
The left case did not present halo sign while the presence of halo in the right one is doubtful. The perinodular blood flow is questionable in the right while unequivocal in the left case. Taking these into account, the risk of a follicular tumor is relatively low in the right, while very high in the right case. We indicated scintigraphy in the left case which disclosed an autonomously functioning nodule.