title: Lipomatous/Extensively Vacuolated Ependymoma with Signet-Ring Cell-Like Appearance: Analysis of a Case with Extensive Literature Review.
abstract: "Lipomatous" and "extensively vacuolated" are descriptive captions that have been used to portray a curious subset of ependymomas distinctively bearing cells with a large vacuole pushing the nucleus to the periphery and, thus, simulating a signet-ring cell appearance. Here, we would like to report the first ependymoma of this kind in a Latin American institution. A 16-year-old boy experienced cephalea during three months. Magnetic resonance imaging scans showed a left paraventricular tumour which corresponded to anaplastic ependymoma. Intriguingly, it was also composed of cells with single or multiple hollow cytoplasmic vacuoles sometimes giving a signet-ring cell-like configuration. Immunolabeling of these showed membrane positivity for GFAP, PS100, and CD99, while Ki-67 expression was null. Ultrastructural examination of retrieved paraffin-embedded tissue showed the presence of scarce microlumina filled with microvilli but failed to demonstrate any content in such optically empty vacuoles as only scant granulofibrillary debris was observed. A schism prevails at present regarding these unusual morphological variants, being either "lipomatous" or "vacuolated" based mainly on the EMA immunoprofile. This, however, is a misappropriate approaching. Could it be that perhaps we are dealing with the same histopathological entity or it may simply happen that fixation and artefacts cannot allow for their proper identification?
authors.affiliation: Department of Neuropathology, National Institute of Neurology & Neurosurgery "Manuel Velasco Suárez", Tlalpan, Mexico City, Mexico.
authors.forename: Miguel Fdo
authors.identifier: 0000-0002-3201-1922
authors.initials: MF
authors.lastname: Salazar
authors.affiliation: Department of Neuropathology, National Institute of Neurology & Neurosurgery "Manuel Velasco Suárez", Tlalpan, Mexico City, Mexico.
authors.forename: Martha Lilia
authors.initials: ML
authors.lastname: Tena-Suck
authors.affiliation: Laboratory of Experimental Neuropathology, National Institute of Neurology & Neurosurgery "Manuel Velasco Suárez", Tlalpan, Mexico City, Mexico.
authors.forename: Alma
authors.initials: A
authors.lastname: Ortiz-Plata
authors.affiliation: Department of Neuropathology, National Institute of Neurology & Neurosurgery "Manuel Velasco Suárez", Tlalpan, Mexico City, Mexico.
authors.forename: Citlaltepetl
authors.initials: C
authors.lastname: Salinas-Lara
authors.affiliation: Department of Neuropathology, National Institute of Neurology & Neurosurgery "Manuel Velasco Suárez", Tlalpan, Mexico City, Mexico.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rembao-Bojórquez