Oncocytic Nodule/Hürtle Cell Tumors
Formerly oncocytic lesions were regarded as a definite entity, but this classification is no longer used. Cytopathologists define oncocytic cells as follows: “Oncocytic follicular cells in the thyroid, known as Hürtle cells, are characterized by large size, polygonal to square shape, distinct cell borders, voluminous granular and eosinophilic cytoplasm, and a large, often hyperchromatic nucleus with prominent cherry pink macronucleoli”. The proliferation of oncocytes gives rise to hyperplastic and neoplastic nodules. Oncocytic cells may behave as follicular carcinomas including capsular and vascular invasion, or they may behave as papillary carcinomas showing papillary architecture.