important since widely invasive tumors can have outcomes with a 55% mortality rate. Histology Hürthle cells arise from the follicular epithelium. Key features of these oncocytic cells include a granular cytoplasm that stains eosinophilic (pink on H&E stain) and a vesicular nucleus with a large nucleolus. A Hürthle cell is larger than a follicular cell, and its cellular material stains eosinophilic. Hürthle cells also tend to be large, polygonal cells with distinct cell borders. The cytoplasm of the oncocytes in Hürthle cell adenomas and carcinomas is characterized by an eosinophilic granular nature, which is commonly due to the oncocytes' high content of mitochondria. Some of these cells can contain up to 5,000 mitochondria, which fills the cytoplasm to the point of nearly excluding other organelles. This high amount of mitochondria is reported to be a result of mutations in the mitochondrial DNA. Some scientists have identified these mutations as deletions in the mitochondrial DNA of Hürthle cells found in neoplasms and Hashimoto's thyroiditis. Treatment A non-minimally invasive Hürthle cell carcinoma is typically treated by a total thyroidectomy followed by radioactive iodine therapy. A Hürthle cell adenoma or a minimally invasive tumor can be treated by a thyroid lobectomy, although some surgeons will perform a total thyroidectomy to prevent the tumor from reappearing and metastasizing. A modified radical neck dissection may be performed for clinically positive lymph nodes. History The Hürthle cell is named after German histologist Karl Hürthle, who investigated thyroid secretory function, particularly in dogs. However, this is a misnomer since Hürthle actually described parafollicular C cells. The cell known as the Hürthle cell was first described in 1898 by Max Askanazy, who noted it in patients with Graves' disease. See also Adenoma Oncocytoma Oxyphil cell References External links EndocrineWeb at endocrineweb.com HKU at hku.hk Image at upmc.edu Cells