{Reference Type}: Journal Article {Title}: Management of Poorly Differentiated Thyroid Cancer and Differentiated High-Grade Thyroid Carcinoma. {Author}: Alam IS;Patel KN; {Journal}: Surg Clin North Am {Volume}: 104 {Issue}: 4 {Year}: 2024 Aug {Factor}: 3.537 {DOI}: 10.1016/j.suc.2024.02.005 {Abstract}: Thyroid carcinoma of follicular cell origin exists on a histopathologic and clinical spectrum. The authors focus on the category of tumors that fall between the very favorable well-differentiated thyroid carcinomas and the very unfavorable anaplastic thyroid carcinomas. These intermediately aggressive tumors include poorly differentiated thyroid carcinoma and the newly defined differentiated high-grade thyroid carcinoma. Both diagnoses require certain histopathologic requirements be met in order to accurately identify these tumors post-operatively. Management remains primarily surgical though adjunctive treatments such as molecular targeted therapies (eg, tyrosine kinase inhibitors) and differentiation therapy (to restore tumor response to radioactive iodine) are also becoming available.