[8] On few occasions, patients with Hürthle cell carcinoma have distant metastases in the lungs or surrounding bones.

Since the size and growth pattern of the tumor cannot be used to determine malignancy, although larger tumors have higher incidence of malignancy, Hürthle cell adenomas and carcinomas have to be separated by the presence of both capsular invasion and vascular invasion in the case of carcinomas, or their absence in the case of adenomas.

[2] Key features of these oncocytic cells include a granular cytoplasm that stains eosinophilic (pink on H&E stain), which is commonly due to the oncocytes' high content of mitochondria, and a vesicular nucleus with a large nucleolus.

[2] This high amount of mitochondria is reported to be a result of mutations in the mitochondrial DNA.

[2] Some scientists have identified these mutations as deletions in the mitochondrial DNA of Hürthle cells found in neoplasms and Hashimoto's thyroiditis.

[8] A non-minimally invasive Hürthle cell carcinoma is typically treated by a total thyroidectomy followed by radioactive iodine therapy.

[6] A modified radical neck dissection may be performed for clinically positive lymph nodes.