Objective: To assess whether the cytologic appearance of aspirates from toxic nodular goiter is substantially modified during the course of therapy with thyrostatic drugs.
Study design: Morphometric features of thyrocyte nuclei in aspirates obtained from nontoxic nodular goiter (NTNG), toxic nodular goiter before treatment (TNG-untreated) and toxic nodular goiter during thyrostatic administration (TNG-treated) were examined. The relationship between the degree of morphologic changes and the duration of therapy was evaluated. An analysis of the composition of aspirates was also performed.
Results: The sizes of thyrocyte nuclei in the TNG-untreated group were larger than in the NTNG and TNG-treated groups, and treatment with thyrostatics was accompanied by a gradual decrease in the sizes of thyrocyte nuclei. However, karyometric features showed a tendency to increase again in patients treated for longer than 1 year, with the variability of nuclear size in a smear (anisokaryosis) increasing more markedly than the mean size of nuclei. Moreover, in those patients, nuclei with visible nucleoli were found.
Conclusion: Only long-term therapy with thyrostatic drugs leads to changes in the microscopic appearance of smears obtained by fine needle aspiration biopsy (FNAB) of the thyroid relevant to cytologic diagnosis. Thus, FNAB can be performed successfully after the onset of treatment with thyrostatics if the cytologist is informed of the time scale of treatment in each case.