Follicular Neoplasms of the Thyroid

OBJECTIVE: Fine needle aspiration of the thyroid is limited in differentiating hyperplastic nodular goiters from true follicular neoplasms and in separating follicular adenomas from follicular carcinomas. The present study was done to evaluate if a panel of morphologic and morphometric parameters of the thyroid and ploidy status, either alone or in combination, would help differentiate hyperplastic nodular goiters from follicular adenomas and carcinomas. STUDY DESIGN: Fine needle aspiration smears of 75 cases classified as follicular neoplasms of the thyroid were studied for morphologic (cellularity, colloid and cellular patterns) and morphometric parameters (nuclear diameters and nucleoli). RESULTS: Of the large number of parameters utilized in this study, only two of the cellular patterns (honeycomb and single dispersed) and the average maximum nuclear diameter showed trends in differentiating these lesions. CONCLUSION: Based on these patterns and nuclear diameter (9 microns), we developed a decision tree classification that separated the benign from malignant lesions (follicular carcinomas) with a sensitivity and specificity of 92.8% and 57.4%, respectively.