Low- and Negative-Pressure Hydrocephalus: New Report of Six Cases and Literature Review.

Low- or very-low-pressure hydrocephalus is a serious and rare phenomenon, which is becoming better known since it was first described in 1994 by Pang and Altschuler. Forced drainage at negative pressures can, in most cases, restore the ventricles to their original size, thus achieving neurological recovery. We present six new cases that suffered this syndrome from 2015 to 2020: two of them after medulloblastoma surgery; a third one as a consequence of a severe head trauma that required bifrontal craniectomy; another one after craniopharyngioma surgery; a fifth one with leptomeningeal glioneuronal tumor; and, finally, a patient with a shunt for normotensive hydrocephalus.

Diffuse leptomeningeal glioneuronal tumor: A review of diagnosis and management with an illustrative case.

Diffuse leptomeningeal glioneuronal tumors (DLGNTs) are a rare indolent neoplasm described in the 2016 WHO classification of tumors of the central nervous system (CNS). We describe a case of an 11 year old boy who initially presented intermittent headache, low back pain and communicating hydrocephalus, misdiagnosed as having tuberculous meningitis. Further clinical deterioration with seizures was observed and follow-up MRI showed further aggravation of leptomeningeal enhancement in the basal cisterns.

[Olfactory ensheathing cell tumour: case report and literature review].

Olfactory ensheathing cells are glial cells located in the olfactory bulb and nerve. Microscopically, both olfactory ensheathing cells and Schwann cells have similar morphological and immunohistochemical features. However, olfactory ensheathing cells are negative for Leu-7(CD-57), whereas Schwann cells are positive.

[Nitric oxide in malignant astrocytes].

Introduction: One of the different molecules involved in the development of astrocytomas is nitric oxide (NO), a gaseous radical that, depending on the cell type and the experimental paradigm selected in the pathology, can play either a cytotoxic or a cytoprotective role.

Development: During the development of an astrocytoma NO acts as a tumouricidal agent, although it can also alter vascular reactivity and lead to neovascularisation, thereby contributing to the invasive capacity (aggressiveness) of the tumour. One of the mechanisms of tumoural progression consists in the protein inactivation resulting from the NO nitration of tyrosine from proteins coded for by tumour-suppressing genes, such as p53.