Thyroid Oncocytic Cell in Cytological and Histologic Reports: Institutional Experience

Purpose: Oncocytic cell tumors, due to historical and clinical reasons, tend to be put in a higher risk category compared with other cell type tumors. We tried to define the malignancy risk for this entity. Methods: At our institution, we studied the risk of malignancy associated with a cohort of 107 thyroid nodules aspirates containing oncocytic cells in the cytology report and we have further analyzed other clinical factors. Results: A tendency for higher risk of malignancy in male sex was found (31.3% vs. 15.4% in women), the difference, however, was not statistically significant (P = 0.291). Total thyroidectomy was the preferred surgical approach and only 10.3% of patients were submitted to lobectomy. Histopathology reports documented 46.7% hyperplastic/adenomatoid nodules, 31.8% adenomas, 12.1% papillary carcinoma, 3.7% oncocytic cell carcinoma, 2.8% lymphocytic thyroiditis and 1.9% poorly differentiated carcinoma. Benign nodules (Bethesda Class II) exhibited a 9.7% malignancy risk; Class III exhibited a 20% malignancy risk; Class IV exhibited a 18.4% malignancy; Class V exhibited a 16% malignancy risk and Class VI exhibited a 100% malignancy risk. Overall histologic data from the aspirated nodules showed a risk of malignancy of 17.8%. Conclusion: Our study seems to suggest that in the presence of oncocytic cells there may be a tendency for a higher than expected malignancy rate. Clinical factors appear to be insufficient to base our management decisions with confidence and molecular markers are still under development. Therefore, surgery may stand as the favored option in this setting.