[Usefulness of paraffin embedding as complementary technic in the diagnosis of thyroid aspirates].

PURPOSE

To compare the diagnostic value of conventional direct cytologic smears and paraffin embedding in the preparation of samples obtained by fine needle aspiration (FNA) biopsy.

METHODS

Direct smears and paraffin embedding preparations were examined from 100 thyroid lesions. In 9 cases, the FNA smears and paraffin embedding blocks were, in addition, compared with surgical thyroid specimens.

RESULTS

The FNA samples were adequate for diagnosis in the great majority of cases (93/100). In 72 aspirates, both smears and paraffin embedding preparations were adequate. In 17 cases only he latter preparations and in 4 specimens only the smears were considered adequate. When both smears and paraffin blocks were available (72 aspirates), there was diagnostic agreement in 63 cases. Overall the diagnostic percentage of FNA/paraffin-block preparations was 95.7% and of FNA/conventional smears was 81.7%. Statistical analysis demonstrated that paraffin blocks increased the diagnostic accuracy of thyroid FNA (p < 0.01).

CONCLUSION

Our data point out to the value of complementing conventional FNA smears with paraffin embedding preparations for the diagnosis of thyroid lesions.