Hürthle cells are characterized as enlarged epithelial cells with abundant eosinophilic granular cytoplasm as a result of altered mitochondria. They generally stain pink and are prominently found in histological sections of thyroid glands affected with Hashimoto's.
A Hürthle cell adenoma is a type of thyroid benign tumor that, in rare cases, has the potential to become malignant and metastasize (Hürthle cell carcinoma). Hürthle cells are also found in Hashimoto's thyroiditis and toxic and nontoxic nodular goiter. Hürthle cells are hypothesized to be of follicular epithelial origin.
^M. Askanazy. Pathologisch-anatomische Beiträge zur Kenntniss des morbus basedowii, insbesondere uber die dabei auftretende Muskelerkrankkung. Deutsches Archiv für klinische Medicin, Leipzig, 1898, 61:118-186.