Panel A shows the relative incidence of the main types of thyroid cancer in the United States, and Panel B the relative frequency of pathologic variants of papillary thyroid carcinoma, with their corresponding main driver mutations shown in parentheses (the symbol > indicates more frequent than). RTK denotes receptor tyrosine kinase. Panel C shows the encapsulated follicular variant of papillary thyroid carcinoma without invasion, which until recently represented 17% of all papillary thyroid carcinomas. This cancer has recently been reclassified as a neoplasm of low malignant potential and is now termed “noninvasive follicular thyroid neoplasm with papillary−like nuclear features” (NIFT−P). This change will result in a corresponding reduction in the number of patients who are considered to have thyroid cancer. The hematoxylin and eosin–stained section in the inset shows the characteristic histologic appearance of an NIFT−P. The encapsulated tumor has a follicular growth pattern and papillary nuclear features, low mitotic rate, and absence of necrosis and capsular or vascular invasion.