MORPHOLOGIC DIAGNOSIS OF HURTHLE CELL TUMORS OF THE THYROID-GLAND

Despite difficulties in differential diagnosis, aspiration cytology of fers unique advantages in the preoperative diagnosis of Hurthle cell ( HC) tumors of the thyroid gland over immunocytochemistry and micromorp hometry, which have not achieved the anticipated success in the diagno sis of HC tumors. Aspiration cytology is comparable, in terms of speed and accuracy, to microspectrometry of DNA content in HC tumors, a tec hnique that is not convenient for routine use. Detailed morphologic an alysis of 19 characteristics of the smears and of the cells revealed f ive parameters adding to the sensitivity, specificity and reliability of routine diagnosis: HC collection in the form of nests, marked or at least moderate anisocytosis and anisokaryosis, multinucleation and em phasized nucleoli. All five criteria are found in > 70% of HC tumors, and the rate of false positives is < 50%. The simultaneous presence of three or four of these five parameters occurred in 70-90% of HC tumor s and would lead to a false-positive diagnosis of HC tumors in only 30 % of cases. Routine cytologic diagnosis of HC tumors of the thyroid gl and may be improved by adoption of these criteria.