In [[the 2022 World Health Organization classification of tumors of the pituitary gland]], nonfunctioning PitNETs are classified according to their frequency as [[silent gonadotroph tumor]]s, [[silent corticotroph tumor]]s, [[silent immature PIT1-lineage tumor]]s, [[null cell tumor]]s, and other tumors 
((Wan XY, Chen J, Wang JW, Liu YC, Shu K, Lei T. Overview of the [[2022]] WHO Classification of Pituitary Adenomas/Pituitary Neuroendocrine Tumors: Clinical Practices, Controversies, and Perspectives. Curr Med Sci. 2022 Dec;42(6):1111-1118. doi: 10.1007/s11596-022-2673-6. Epub 2022 Dec 22. PMID: 36544040.))