L-thyroxine effects on thyreocytes and Hürthle cells in nodular hyperplastic goiter on fine needle aspiration samples. Morphometric evaluation.

A morphometric study was performed on the thyreocytes and Hürthle cells in 20 cases of nodular hyperplastic goiter (NHG) and in 8 cases of Hürthle cell-rich NHG. The study was carried out on cytologic samples obtained by fine needle aspiration twice from the same nodules in a selected series of patients before and after L-thyroxine therapy with the aim of evaluating the morphometric nuclear variations induced by that therapy. Thyreocytes and Hürthle cells were evaluated for nuclear Area, Perimeter, Maximum Diameter, Form Elliptic and Form Perimeter using a planimetric instrument. A statistically significant reduction in nuclear size was observed in 18 of 20 cases of NHG after L-thyroxine therapy, but the nuclear shape factors were modified only slightly or not at all. A slight reduction in the nuclear size of Hürthle cells was observed in five and an increase in the remaining three cases, but these differences were not statistically significant. Virtually no changes in shape factors were observed in this group of lesions before or after the therapy. These data are discussed and compared to the results of other series. Our results suggest that morphometry may be useful in the follow-up of NHG to evaluate the effects of L-thyroxine and that this therapy reduces the size of thyreocytes; the therapy, however, seems to have little or no effect on Hürthle cells