Variable response to radioactive iodine treatment in poorly differentiated thyroid carcinoma

The global incidence of thyroid cancer has steadily increased, however mortality has remained unchanged as most thyroid malignancies are well-differentiated (WDTC) with indolent behavior. The incidence, however, of poorly differentiated (PDTC) and anaplastic thyroid cancer (ATC) have also increased proportionally and these are aggressive tumors associated with significant morbidity and mortality (1). PDTC has been recognized as a distinct entity that represents an intermediate position in the sequence of de-differentiation from WDTC to ATC with unique histopathology, molecular abnormalities, and diagnostic criteria (2).