Oncocytes, oxyphils, Hürthle, and Askanazy cells: morphological and molecular features of oncocytic thyroid nodules.

Our understanding of oncocytic change in thyroid nodules is evaluated in light of the recent progress in understanding the mitochondrial DNA, its mutations, and somatic mutations that affect mitochondrial function. These changes are largely unrelated to the genetic events that result in proliferation and neoplastic transformation of thyroid follicular epithelial cells. The criteria for diagnosing lesions that are composed predominantly of oncocytic cells are the same as those applied to follicular lesions that do not contain oncocytic cells, including follicular variant papillary carcinomas, based on nuclear morphology, immunohistochemical profiles, and molecular markers.