title: Embryonal Tumor With Abundant Neuropil and True Rosettes: A Distinct Immunohistochemical Pattern.
abstract: Embryonal tumors with abundant neuropil and true rosettes (ETANTR) are rare pediatric embryonal neoplasms that combine features of neuroblastoma and ependymoblastoma. We report a distinct immunohistochemical-staining pattern of ETANTR in a 12-month-old baby who presented with a supratentorial mass. The tumor exhibited a characteristic biphasic pattern of neuropil-rich areas and patchy cellular neuropil-poor areas. The neoplastic cells in neuropil-rich areas are diffusely immunoreactive to chromogranin A, synaptophysin, neurofilament, and CD56, but show no immunoreactivity to nestin, SOX2, WT-1, β-catenin, and vimentin. While the cells in neuropil-poor areas, including ependymoblastic and Flexner-Wintersteiner rosettes, are diffusely immunoreactive to nestin, SOX2, WT-1, β-catenin, and vimentin but show no immunoreactivity to chromogranin A, synaptophysin, neurofilament, and CD56. Ependymoblastic rosettes show luminal membranous immunoreactivity to EMA. We believe that ETANTR has a distinct histologic and immunohistochemical pattern supporting the embryonal origin of this tumor with divergent neuroblastic and primitive glial differentiation.
authors.affiliation: *Pathology Department, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE †Department of Pathology, University of Utah, Primary Children's Hospital, Salt Lake City, UT.
authors.forename: Suhail
authors.initials: S
authors.lastname: Al-Salam
authors.forename: Mouied
authors.initials: M
authors.lastname: Al Alashari
mesh_terms: D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D009373:Neoplasms, Germ Cell and Embryonal / Q000378:metabolism / Q000473:pathology*; D019581:Neuropil / Q000378:metabolism*