In histopathological diagnosis, difficulties exists in differentiating between follicular adenoma and follicular carcinoma of the thyroid. As the histopathological criteria have limitations, there is great need for further variables which can
give
information on the biological behavior of the thyroid follicular tumor. Recent years have brought increased enthusiasms for DNA determination by flow cytometry as a method of characterizing thyroid tumors. But the diagnostic and prognostic
importance of
flow cytometric DNA measurements of thyroid follicular neoplasia is still controversial. The aim of the present study is to determine if flow cytometric DNA measurements are useful in differentiating between follicular adenomas and carcinoma of
the
thyroid. The nuclear DNA content was measured retrospectively in histologically confirmed follicular adenomas in 14 patients, follicular carcinomas in 13 patients and Hurthle cell carinomas in 3 patients with flow cytometric method.
@ES The results were as follows:
@EN 1) The age of patient and the size of the tumor were not statistically significant parameters in differentiating between the follicular adenoma and carcinoma of thyroid.
2) All follicular adenomas showed DNA diploid patterns. Among 15 follicular carcinomas, together with the diploid patterns in 12 cases(80%), aneuploid patterns were also observed in 3 cases(20%). This result means that a diploid DNA pattern in
follicular tumors does not rule out malignancy, while aneuploid is not an unequivocal sign of malignancy.
3) S-phase fraction in follicular carcinomas was significantly higher than that in follicular adenoma. S-phase fraction of thyroid follicular carcinoma with trabecular pattern which is thought to be poor prognosis was significantly higher than
that of
follicular carcinoma with micro-, and macrofollicular pattern. So, the evaluation of the percentage of cells in S-phase seems to contribute a valuable complementary information for individual diagnosis of malignancy in the thyroid follicular
tumors
and
a prognostic factor in patient with thyroid follicular carcinoma.
This study indicates a rather limited clinical value of flow cytometric measurements of DNA in differential diagnosis of the thyroid follicular neoplasia. The long-term clinical follow up is warranted to document further clinical significance of
this
observations.
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