Primary Tumors of the Posterior Pituitary Gland: A Systematic Review of the Literature in Light of the New 2017 World Health Organization Classification of Pituitary Tumors

Case Report: Sellar Ependymomas: A Clinic-Pathological Study and Literature Review

“…Interestingly, Heath et al also reported a case of a pituitary ependymoma occurrence in a horse ( 17 ). In 2017 WHO classification of pituitary tumors, SE, pituicytoma, granular cell tumor, and spindle cell oncocytoma were classified as nosological entities, called primary posterior pituitary tumors, a distinct group of low-grade and non-neuroendocrine neoplasms with TTF-1 immunopositivity ( 18 , 19 ). All these tumors are believed to arise from pituicytes ( 20 ).…”

“…In our analysis, we found two female patients and 11 male patients, suggesting a male inclination, consistent with previous reports, suggesting that males have a higher incidence of ependymoma occurrences than females ( 1 , 4 ). As for the clinical presentation, SEs are often symptomatically similar to nonfunctional pituitary adenomas ( 18 ), with some studies reporting that the duration of symptoms also depends on the histological grade of tumors ( 7 ). We divided the condition into two aspects here.…”

“…Immunostaining analysis provides additional significant information for the correct diagnosis of ependymomas, with positive expression levels of TTF-1, GFAP, S-100, vimentin, EMA, and negative expression levels for secreted pituitary hormones and neural markers, such as synaptophysin ( 10 – 12 , 18 , 21 ). In some cases, GFAP did not appear to be immunoreactive ( 52 ), consistent with 3 out of 13 reported cases of SE, including our patient.…”

“…The use of radiotherapy modalities to treat ependymoma remains controversial, especially in children ( 59 ). Whipple et al reported that radiotherapy is imperative for residual tumors ( 18 ); however, no objective data currently supports this theory ( 3 ). As for SE, 4 cases (4/13 [30.77%]) underwent postoperative radiotherapy, and only one case (1/13 [7.69%]) showed tumor recurrence ( 11 ).…”

“…All these tumors are believed to arise from pituicytes (20). Among them, SE is the least described, and scant effective information is available (18)(19)(20)(21)(22). According to the latest histopathological classification of WHO in 2016, ependymoma was classified into three grades (23).…”