Challenges in the Intraoperative Consultation of Low-Grade Epilepsy-Associated Neuroepithelial Tumors by Cytomorphology in Squash Preparations

<b><i>Introduction:</i></b> Low-grade epilepsy-associated neuroepithelial tumors (LEATs) create a diagnostic challenge in daily practice and intraoperative pathological consultation (IC) in particular. Squash smears are extremely useful in IC for accurate diagnosis; however, the knowledge on cytopathologic features of LEATs is based on individual case reports. Here, we discuss the 3 most common and well-established entities of LEATs: ganglioglioma (GG), dysembryoplastic neuroepithelial tumor (DNT), and papillary glioneuronal tumor (PGNT). <b><i>Methods:</i></b> Thirty patients who underwent surgery for GG, DNT, and PGNT between 2001 and 2021 were collected. Squash smears prepared during intraoperative consultation were reviewed by 1 cytopathologist and an experienced neuropathologist. <b><i>Results:</i></b> Among the 30 tumors, 16 (53.3%) were GG, 11 (36.6%) DNT, and 3 (10%) PGNT. Cytomorphologically, all of the 3 tumor types share 2 common features such as dual cell population and vasculocentric pattern. GG smears were characteristically composed of dysplastic ganglion cells and piloid-like astrocytes on a complex architectural background of thin- to thick-walled vessels. DNT, on the other hand, showed oligodendroglial-like cells in a myxoid thin fibrillary background associated with a delicate capillary network. Common cytological features of PGNT were hyperchromatic cells with narrow cytoplasm surrounding hyalinized vessels forming a pseudopapillary pattern and bland cells with neuroendocrine nuclei dispersed in a neuropil background. <b><i>Conclusion:</i></b> A higher diagnostic accuracy can be obtained when squash smears are applied with frozen sections. However, it is important to integrate clinical and radiologic features of the patient as well as to know the cytopathologic features of the LEAT spectrum in the context of differential diagnosis to prevent misinterpretation in the IC.

Management of Choroid Plexus Papillomas

Introduction: Choroid plexus papillomas are rare neuroepithelial tumors found primarily in children. It represents less than 1% of all central nervous system tumors. Materials and methods: A retrospective study including 14 patients with choroid plexus papilloma tumors were performed at the Neurosurgery Department in Ait IDDIR Health Hospital Establishment between January 2010 and December 2017. In each case, diagnosis was made clinically and confirmed radiologically and histo-pathologically. All patients were operated. Results and discussion: The mean age was 26 years (ranged 3 months –48 years) .In our department, we grouped together 14 cases of choroid plexus papilloma tumors. For mortality we had one case who died during surgery, survival rate for 04 years is 100% .We had not recurrence during the study period.All patients had intracranial hypertension (HIC) without neurological deficit and benefited from brain CT, MRI and an Angiography. The location of the tumor was: Lateral ventricle, Fourth ventricle, Third ventricle. All patients underwent surgical excision with or without ventriculo-peritoneal shunt. Conclusion: Choroid plexus papillomas are rare neuroepithelial tumors, typically considered benign lesions, derived from the choroid plexus and appear like cauliflower.

Recurrent fusions in PLAGL1 define a distinct subset of pediatric-type supratentorial neuroepithelial tumors

Ependymomas encompass a heterogeneous group of central nervous system (CNS) neoplasms that occur along the entire neuroaxis. In recent years, extensive (epi-)genomic profiling efforts have identified several molecular groups of ependymoma that are characterized by distinct molecular alterations and/or patterns. Based on unsupervised visualization of a large cohort of genome-wide DNA methylation data, we identified a highly distinct group of pediatric-type tumors (n = 40) forming a cluster separate from all established CNS tumor types, of which a high proportion were histopathologically diagnosed as ependymoma. RNA sequencing revealed recurrent fusions involving the pleomorphic adenoma gene-like 1 (PLAGL1) gene in 19 of 20 of the samples analyzed, with the most common fusion being EWSR1:PLAGL1 (n = 13). Five tumors showed a PLAGL1:FOXO1 fusion and one a PLAGL1:EP300 fusion. High transcript levels of PLAGL1 were noted in these tumors, with concurrent overexpression of the imprinted genes H19 and IGF2, which are regulated by PLAGL1. Histopathological review of cases with sufficient material (n = 16) demonstrated a broad morphological spectrum of tumors with predominant ependymoma-like features. Immunohistochemically, tumors were GFAP positive and OLIG2- and SOX10 negative. In 3/16 of the cases, a dot-like positivity for EMA was detected. All tumors in our series were located in the supratentorial compartment. Median age of the patients at the time of diagnosis was 6.2 years. Median progression-free survival was 35 months (for 11 patients with data available). In summary, our findings suggest the existence of a novel group of supratentorial neuroepithelial tumors that are characterized by recurrent PLAGL1 fusions and enriched for pediatric patients.

Epidemiological Characterization of Brain Tumors in Colombia, a 10-Year Period

Introduction: Central nervous system tumors are rare; in 2015 they represented approximately 1.4% of new cancer diagnoses, causing 2.6% of deaths by cancer that year. In Colombia, there are few reports on the epidemiology of brain tumors, and those that exist are local databases that do not have a rigorous and massive registry. Due to limited epidemiological information in our country, this document aims to characterize the epidemiology of brain tumors in Colombia over a 10-year period. Methods: A retrospective descriptive observational study was conducted, using databases of population-based cancer registries in Colombia. We extracted information from a 10-year period recorded in patients with tumors without age group restriction. A descriptive analysis was carried out for all the variables considered, the incidence and mortality rates per 100,000 person years were calculated. Statistical software Stata 14.0 was used. Results: Our analysis was performed with a population of 775 adult patients and 123 pediatric patients, with an incidence of 1.55 per 100.000 individuals in the pediatric population and 3.19 per 100.000 individuals in the adult population. The mortality rate for pediatric and adult patients was 0.063 per 100.000 individuals and 1.86 per 100.000 individuals respectively. The most frequent tumors in the pediatric age group were neuroepithelial tumors, embryonal tumors and ependymal tumors, whereas for adults, the most frequent were neuroepithelial tumors, meningiomas and hematolymphoid tumors. Conclusions: This study constitutes the most recent work on the epidemiology of brain tumors in Colombia. There was a clear general underreporting and statistics lower than those compared with the literature. It is intended to expand coverage and data collection in population-based cancer registries.