Morphometric Study on Fine Needle Aspirates from Follicular Adenoma and Follicular Carcinoma of the Thyroid

Chu, Young Chae; Cha, Hee Jung; Min, Soo Kee; Kim, Joon Mee; Hwang, Tae Sook

Abstract

Fine needle aspiration cytology of "cold" nodules of the thyroid has proved to be of great value in their preoperative diagnosis. Most types of thyroid tumors are readily recognizable from characteristic cellular patterns in the smears of needle aspirates. But follicular neoplasms present some problems because the cytomorphology of the adenomas frequently is same as in carcinoma. For differentiation of benign from malignant follicular neoplasms of the thyroid we tested the usefulness of two objective parameters - nuclear area and perimeter - by morphometry. This study was made on fine needle aspirates from 30 cases with cytologic diagnosis of follicular neoplasm of thyroid. The histologic classification was follicular adenoma in 22 cases and follicular carcinoma in 8 cases. As a reference group we used seven caes with nodular hyperplasia. The smears of aspirates were stained by Papanicolaou method. On each slide 200 randomly selected cells with intact nuclei were measured. The mean value of nuclear area are 25.32+/-5.50 micrometer2, 34.08+/-7.50 micrometer2 and 39.97+/-6.63 micrometer2 in nodular hyperplasia, follicular adenoma, and follicular carcinoma, respectively. The mean value of perimeter are 19.48+/-2.26 micrometer, 22.95+/-2.65 micrometer and 24.78+/-2.23 micrometer in nodular hyperplasia, follicular adenoma and follicular carcinoma, respectively. The mean nuclear areas and perimeters of cells from follicular adenoma were significantly larger than those from nodular hyperplasia (p<0.05). The mean nuclear areas and perimeters of cells from follicular carcinoma were larger than those from follicular adenoma but the differences are not significant statistically(p<0.05). Therefore, morphometric assessment alone is inadequate to predict malignancy in thyroid aspirates.