Preoperative Diagnosis of Neoplastic or Malignant Hürthle Cell Lesions: A Chimera?

OBJECTIVE: We aimed to review all cytological specimens with Hürthle cells (HC) diagnosed in our institution, identify cytological features related to neoplastic (adenoma or carcinoma) and malignant histology, and discuss the role of clinicopathological findings and clinical management in these cases. STUDY DESIGN: We included 359 thyroid fine-needle aspiration cytology cases in our study. We reviewed the clinical and cytological features of surgical cases and correlated them with histological diagnosis. We also reviewed the literature on this issue. RESULTS: We found a significant association between neoplasia and highly cellular smears, the absence of colloid, the presence of microfollicles, large-cell dysplasia, prominent nucleoli or macronucleoli, coarse chromatin, nuclear grooves and inclusions, nuclear irregularity, and pleomorphism. The absence of colloid, high cellularity, > 25% of isolated HC, the presence of tridimensional groups, transgressing vessels, nuclear irregularity, prominent nucleoli or macronucleoli, coarse chromatin, hyperchromatism, pleomorphism, and diffuse large-cell dysplasia were features significantly associated with malignancy. CONCLUSIONS: No cytological feature alone can predict histological outcome, but all findings related to a neoplastic or malignant histology must be assessed. Individualized management protocols should be developed in each institution.