Nodular goiter

Oxyphilic metaplasia

Benign hyperplastic nodule	Oxyphilic cancer


Cohesive groups of oxyhilic cells can be seen. Only a few dissociated cells can be found. The chromatine structure is blunt. Moreover, diffuse colloid precipitate can observed. The risk if a lesion is an oxyphilic tumor is less than 10% .	Although oxyphilic cells do not present large prominent nucleoli, they tend to dissociate. The latter property counts more than the former. The risk of oxyphilic tumor is more than 50%.
Benign hyperplastic nodule - Case 29	Oxyphilic variant of papillary cancer - Case 70


The patterns are very similar. The only difference is in the tendency of cells to dissociate. This is only limited in the case of hyperplastic nodule while more pronounced in the case of oxyphilic adenoma.
Benign hyperplastic nodule - Case 10	Oxyphilic adenoma - Case 3


On the presence of dissociated cells, prominent nucleoli and the lack of colloid, the risk of an oxyphilic tumor is greater than 50%. The presence of an inclusion has only limited significance in metaplastic cells.	The whole pattern corresponds to a non-tumorous lesion: oxyphilic cells are mostly in sheets, only a few cells exhibit nucleolus and there is colloid in the background. The presence of grooves has only limited significance in metaplastic cells.
Benign hyperplastic nodule - Case 26	Oxyphilic adenoma - Case 7


The cytological pattern is identical in these cases: most if not all thyrocytes exhibit oxyphilic changes, they present prominent nucleoli and there is an unequivocal tendency of cells to dissociate. The risk of a Hürthle-cell tumor was much greater than 50% in both cases.
Benign hyperplastic nodule - Case 52	Oxyphilic adenoma - Case 2


Every cell presents oxyphilic metaplasia, contains large promient nucleoli and there is no colloid in the background. These properties raise the possibility of an oxyphilic tumor. On the other hand the lack of tendency to dissociate stands againts this possibility. The risk of an oxyphilic tumor (either an adenoma or an oxyphilic variant of follicular cancer) based solely on the cytological pattern was more than 50%.	Microfollicular proliferation is more pronounced and tendency of cells to dissociate can be observed. The risk of an oxyphilic tumor was more than 80%.

Any thyroid disease and even a healthy thyroid may present oxyphilic metaplasia. In certain cases great proportion of cells of a benign hyperplastic nodule exhibit this feature. In such cases the possibility of a Hürthle-cell tumor has to be considered. The lack of prominent nucleoli and the lack of dissociated, single oxyphilic cells argue against the possibility of a tumor and argue for a non-tumorous lesion. Other cytological signs, i.e. the presence of colloid or lymphocytes may be of help, but the clear distinction is not possible in every case. In most cases we can decide on cytology which type of an oxyphilic carcinoma has to be raised, the follicular or papillary carcinoma. If nuclei lack inclusion and groove, the risk of the latter is very low. As regards the former, the sonographic signs of a capsule has to be taken ito account. Most follicular tumors present either halo sign or type 2 vascular pattern. If these signs are lacking, the risk of a Hürthle-cell adenoma is significantly lower, while that of an oxyphilic variant of a follicular carcinoma is negligible.