ABSTRACT
Purpose To investigate the clinicopathologic features of RELA fusion-positive ependymoma. Methods The clinical manifestations, radiological appearance, pathological and immunohistochemical findings and immunophenotype in 11 cases of RELA fusion-positive ependymoma were retrospectively analyzed, and the related literature was reviewed. Results Eleven cases of RELA fusion-positive ependymomas occured in the supratentorial region. There were 6 males and 5 females ranged in age from 3-56 years (median = 27). Imaging showed the occupying lesion in the supratentorial region. Histologically, a distinctive branching network of delicate capillaries and (true) ependymal rosettes/pseudorosettes were observed. Immunohistochemically, the tumor cells were diffusely positive for GFAP, L1 CAM and Cyclin D1, and EMA staining with dot-like cytoplasmic reactivity were observed. Most of the cases showed a positive for nestin, but all of the cases showed negative for Olig-2. Conclusion RELA fusion-positive ependymomas usually affect the supratentorial region of young people, which have unique immunophenotype and gene phenotype, and are characterized by poor prognosis. This type of ependymoma should be identified in the diagnosis and differential diagnosis.