Overview of the New World Health Organization Classification of Pituitary Neuroendocrine Tumors

The 5th edition of the World Health Organization(WHO)classification of endocrine and neuroendocrine tumors was revised in 2022. A major nomenclature change was from "adenoma" to "pituitary neuroendocrine tumor"(PitNET). Tumors are classified based on the cell lineage as determined by expression of transcription factors, such as, PIT1, TPIT, and SF1. Therapeutic modalities available for management of functioning PitNETs include surgery, medical treatment, and irradiation. Transsphenoidal surgery is the gold-standard surgical treatment. The aim of the present study was to summarize changes from the previous edition of the WHO classification and discuss topics regrading PIT1, TPIT, and SF1-lineage PitNETs with reference to clinicopathological findings.