{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T13:45:17Z","timestamp":1788356717427,"version":"build-2803163510"},"reference-count":41,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,3,17]],"date-time":"2021-03-17T00:00:00Z","timestamp":1615939200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:p>Pituitary tumors are very complex and heterogeneous and have a very wide range of proliferative and aggressive behaviors, and how to define and classify these tumors remains controversial. This review summarizes the epidemiology and progress in the classification and definition of pituitary tumors, as well as controversial issues. Based on the results of radiologic and autopsy studies, the prevalence of pituitary tumors has recently increased significantly. However, the majority of pituitary tumors are incidentally discovered and asymptomatic, and such tumors are called pituitary incidentalomas. Most of these incidentalomas do not induce symptoms, remain stable in size, and do not need treatment. The recent revised classification strategies mainly depend on immunohistochemistry (IHC) to detect pituitary hormones and pituitary transcription factors; therefore, the accuracy of diagnosing pituitary tumors has improved. Although new classification strategies and definitions for pituitary tumors have been presented, there are still some controversies. The term pituitary neuroendocrine tumor (PitNET) was proposed by the International Pituitary Pathology Club, and this terminology can encompass the unpredictable malignant behavior seen in the subset of aggressive pituitary adenomas (PAs). However, some endocrinologists who oppose this change in terminology have argued that the use of tumor in the terminology is misleading, as it gives PAs a harmful connotation when the majority are not aggressive. Such terminology may add new ambiguity to the origin of PAs and unnecessary anxiety and frustration for the majority of patients with benign PAs. The classification of aggressive PAs mainly relies on subjective judgment of clinical behavior and lacks objective biomarkers and unified diagnostic criteria. However, the term \u201crefractory\u201d could more accurately represent the characteristics of these tumors, including their clinical behaviors, radiological features, and pathologic characteristics. Moreover, the diagnostic criteria for refractory PAs are stricter, more objective, and more accurate than those for aggressive PAs. Early identification of patients with these tumors through recognition and increased awareness of the definition of refractory PAs will encourage the early use of aggressive therapeutic strategies.<\/jats:p>","DOI":"10.3389\/fendo.2021.604644","type":"journal-article","created":{"date-parts":[[2021,3,17]],"date-time":"2021-03-17T10:47:34Z","timestamp":1615978054000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":34,"title":["How to Classify and Define Pituitary Tumors: Recent Advances and Current Controversies"],"prefix":"10.3389","volume":"12","author":[{"given":"Congxin","family":"Dai","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Kang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaohai","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yong","family":"Yao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haijun","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Renzhi","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,3,17]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"87","DOI":"10.1159\/000371806","article-title":"Aggressive Pituitary Tumors","volume":"101","author":"Chatzellis","year":"2015","journal-title":"Neuroendocrinology"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1007\/s00401-017-1769-8","article-title":"The 2017 World Health Organization classification of tumors of the pituitary gland: a summary","volume":"134","author":"Lopes","year":"2017","journal-title":"Acta Neuropathol"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1007\/s40618-018-0901-5","article-title":"Advances and controversies in the classification and grading of pituitary tumors","volume":"42","author":"Laws","year":"2019","journal-title":"J Endocrinol Invest"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1038\/nrc926","article-title":"The pathogenesis of pituitary tumours","volume":"2","author":"Asa","year":"2002","journal-title":"Nat Rev Cancer"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1002\/cncr.20412","article-title":"The prevalence of pituitary adenomas: a systematic review","volume":"101","author":"Ezzat","year":"2004","journal-title":"Cancer-Am Cancer Soc"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2265.2009.03667.x","article-title":"Prevalence of pituitary adenomas: a community-based, cross-sectional study in Banbury (Oxfordshire, UK)","volume":"72","author":"Fernandez","year":"2010","journal-title":"Clin Endocrinol (Oxf)"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2006-1668","article-title":"High prevalence of pituitary adenomas: a cross-sectional study in the province of Liege, Belgium","volume":"91","author":"Daly","year":"2006","journal-title":"J Clin Endocrinol Metab"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1530\/EJE-14-0144","article-title":"The incidence rate of pituitary adenomas in western Sweden for the period 2001\u20132011","volume":"171","author":"Tj\u00f6rnstrand","year":"2014","journal-title":"Eur J Endocrinol"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1530\/EJE-15-0189","article-title":"The epidemiology of pituitary adenomas in Iceland, 1955-2012: a nationwide population-based study","volume":"173","author":"Agustsson","year":"2015","journal-title":"Eur J Endocrinol"},{"key":"B10","doi-asserted-by":"publisher","first-page":"894","DOI":"10.1210\/jc.2010-1048","article-title":"Pituitary Incidentaloma: An Endocrine Society Clinical Practice Guideline","volume":"96","author":"Freda","year":"2011","journal-title":"J Clin Endocrinol Metab"},{"key":"B11","doi-asserted-by":"publisher","first-page":"101268","DOI":"10.1016\/j.beem.2019.04.002","article-title":"Management of pituitary incidentaloma","volume":"33","author":"Boguszewski","year":"2019","journal-title":"Best Pract Res Cl En"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1097\/00005792-199907000-00004","article-title":"Diagnosis, treatment, and outcome of pituitary tumors and other abnormal intrasellar masses. 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