Oncocytic cells in the punctate of a thyroid gland nodule. Is there a reason to suspect cancer

Oncocytic metaplasia can occur in various thyroid conditions. Individual cells, follicles, or groups of follicles may show signs of oncocytic metaplasia, such as in irradiated thyroid gland, nodular goiter, and chronic lymphocytic thyroiditis, as well as in long‑term autoimmune hyperthyroidism (Graves’ disease). Malignant nodes from oncocytic cells are even rarer. According to the world literature, the prevalence of oncocytic carcinoma (OC) among all thyroid cancers is from 3% to 5%. Among nodes that had oncocytic cells in the cytological sample, oncocytic carcinoma is detected in 5.0—49.1% of cases; and the overall prevalence of malignancy among such nodes (including papillary and follicular cancer, oncocytic variant and OC) is 35.8%. Objective — to establish a connection between the presence of oncocytes in punctate thyroid nodules and the detection of cancer on histopathological examination; to investigate the possibility of using the presence of oncocytes in the punctate as a predictor of the presence of cancer. Materials and methods. A monocentric retrospective study was conducted involving 487 patients who underwent primary surgery between January 2019 and December 2023 for nodular and multinodular goiter (TBSRTC III, IV, V). All patients underwent thyroidectomy or hemithyroidectomy, supplemented with neck dissection and lymphadenectomy. Results. Among 487 patients with thyroid nodules categorized as Bethesda III, IV, or V, malignancy was identified in 211 cases. Of these, 36 patients exhibited oncocytic changes in the punctate, while 175 patients did not. In the remaining 276 patients, cancer was not diagnosed, including 60 cases with detected oncocytic cells and 216 cases without such changes on cytological examination. The data were analyzed for each patient group according to the Bethesda classification. The highest test performance (specificity and overall efficiency) was observed in patients with Bethesda III, though sensitivity was zero. Similarly, in patients with Bethesda IV and V, sensitivity remained extremely low, resulting in low overall efficiency despite high specificity. Conclusions. The study did not establish a significant relationship between the presence of oncocytic cells in punctate thyroid nodules (Bethesda III, IV, V) and the subsequent diagnosis of thyroid cancer. Therefore, the presence of oncocytic cells in thyroid nodules cannot be considered a reliable predictor of malignancy. Additionally, the presence of oncocytes does not appear to be a negative prognostic factor for malignancy compared to their absence.