RÉSUMÉ
The fifth edition WHO classification of Tumors of the Central nervous system (WHO-CNS5) integrated new molecular parameters to refine CNS tumor classification. This study aimed to reclassify a retrospective cohort of adult glioma patients according to WHO-CNS5, and assess if overall survival (OS) correlated with the revised diagnosis. Further, the diagnostic impact of methylation profiling (MP) was evaluated. Adult gliomas diagnosed according to 2016 WHO-CNS (n = 226) were evaluated according to WHO-CNS5 criteria. All patients had diagnostic NGS performed. 29 patients had 850k MP performed due to challenging tumor cases. OS was analyzed using Kaplan-Meier plots and log-rank test. 19 patients were reclassified. Specifically, diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma (DAG-G) were reclassified as glioblastoma (n = 15). Shifts to glioblastoma were because of TERT promoter (TERT p ) mutation (n = 9), EGFR amplification (n = 2), EGFR amplification and TERT p mutation (n = 1), and TERT p mutation with gain of chromosome 7, but uncertain chromosome 10 status due to lack of NGS coverage (n = 3). Lower grade IDH-mutant astrocytomas were reclassified as astrocytoma IDH-mutant, WHO grade 4 due to CDKN2A/B homozygous deletion (n = 4). No significant difference in OS was found for reclassified DAG-G in whole group (p = 0.59) and for TERT p mutation only (p = 0.44), compared to glioblastoma. MP resulted in revised diagnosis (n = 2), confirmed diagnosis (n = 15) and no match (n = 12). Our study showed similar overall survival for glioblastoma and DAG patients, supporting that isolated TERT p mutation may have a prognostic role in IDH-wildtype gliomas. Further, our study suggests MP is useful for confirming the diagnoses in challenging tumors.
RÉSUMÉ
ABSTRACT: Central neuropathic pain is a core clinical sign of syringomyelia in humans and Cavalier King Charles Spaniel (CKCS) dogs. This histopathological study used spinal cords from CKCS dogs with syringomyelia to investigate the following conditions: (1) whether specific structural cervical spinal cord entities involved in nociception were affected by loss of neuroparenchyma or other pathological changes in CKCS dogs with pain-related behaviour and phantom scratching, (2) whether pain-related behaviour or phantom scratching correlated with loss of a specific anatomical entity or upregulation of glia cells, and (3) whether syringomyelia-related lesions affected specific functional spinal cord units of nociception. Spinal cord segments C1-C8 from CKCS dogs with magnetic resonance imaging-confirmed syringomyelia and clinical signs of pain and phantom scratching (n = 8) were compared with those from CKCS dogs without syringomyelia (n = 4). Dogs with unilateral scratching (n = 7) had a volume loss ( P = 0.043) of the dorsal horn laminae I-III in the ipsilateral side compared with the contralateral dorsal horn. A clear pattern of ipsilateral changes in the dorsal root entry zone characterised by deafferentation and reorganization of first-order axons into deeper laminae was found in cases with lateralised scratching. Significant changes in cell number density were not found for astrocytes or microglia, suggesting that the dogs represented cases of end-stage syringomyelia and thus could not reveal astrogliosis and microgliosis, which may be involved in the early phases of syrinx development and phantom scratching. The present relationship between clinical findings and dorsal horn and pain pathway pathology in CKCS dogs suggests that these dogs may be of interest as a supplement to experimental model pain research.