title: Refractory pituitary adenoma: a novel classification for pituitary tumors.
abstract: Pituitary adenomas are classified as typical or atypical, invasive or noninvasive, and aggressive or nonaggressive based on pathological features, radiological findings, and clinical behavior. Only pituitary tumors with cerebrospinal and/or systemic metastasis are considered malignant carcinomas. However, some pituitary adenomas with high Ki-67 indexes exhibit aggressive behaviors, such as rapid growth, early and frequent recurrence, and resistance to conventional treatment, even in the absence of metastasis. Novel terminology is needed to define these tumors. Here, we propose the use of the term "refractory pituitary adenoma" to define malignant pituitary tumors exhibiting 1) a high Ki-67 index and rapid growth, 2) early and high frequency of recurrence, 3) resistance to conventional treatments and/or salvage treatment with temozolomide (TMZ), 4) poor prognosis, 5) and a lack of cerebrospinal or systemic metastases. To illustrate the utility of this refractory pituitary adenoma classification and the difficulty in managing disease in these patients, we examined twelve clinical cases. Correctly identifying refractory pituitary adenomas is crucial for improving patient prognoses. Early identification might encourage the early use of aggressive therapeutic strategies to prevent or delay recurrence.
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Congxin
authors.initials: C
authors.lastname: Dai
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Feng
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Sihai
authors.initials: S
authors.lastname: Ma
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Bowen
authors.initials: B
authors.lastname: Sun
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Xinjie
authors.initials: X
authors.lastname: Bao
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Kan
authors.initials: K
authors.lastname: Deng
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Xing
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Lian
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Dingrong
authors.initials: D
authors.lastname: Zhong
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Ma
authors.affiliation: Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Renzhi
authors.initials: R
authors.lastname: Wang
mesh_terms: D000236:Adenoma / Q000145:classification* / Q000473:pathology / Q000628:therapy; D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D001706:Biopsy; D049109:Cell Proliferation; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000627:therapeutic use; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D010911:Pituitary Neoplasms / Q000145:classification* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D016879:Salvage Therapy; D000077204:Temozolomide; D009626:Terminology as Topic; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D018906:Antineoplastic Agents, Alkylating; D019394:Ki-67 Antigen; D003606:Dacarbazine; D000077204:Temozolomide
keywords: aggressive; pituitary adenomas; recurrence; refractory; resistance