Daramola, Adetola Olubunmi

Abstract Background The optimal diagnosis and management of patients with brain tumors currently uses the 2021 WHO integrated diagnosis of histomorphologic and molecular features. However, neuro-oncology practice in resource-limited settings usually relies solely on histomorphology. This study aimed to classify glioma cases diagnosed in the Department of Anatomic and Molecular Pathology, Lagos University Teaching Hospital, using the 2021 WHO CNS tumor classification. Methods Fifty-six brain tumors from 55 patients diagnosed with glioma between 2013 and 2021 were reevaluated for morphologic diagnosis. Molecular features were determined from formalin-fixed paraffin-embedded (FFPE) tissue using immunohistochemistry (IHC) for IDH1-R132H, ATRX, BRAF-V600E, p53, Ki67, and H3-K27M, OncoScan chromosomal microarray for copy number, targeted next generation sequencing for mutation and fusion and methylation array profiling. Results Of 55 central nervous system tumors, 3 were excluded from histomorphologic reevaluation for not being of glial or neuroepithelial origin. Of the remaining 52 patients, the median age was 20.5 years (range: 1 to 60 years), 38(73%) were males and 14(27%) were females. Seventy-one percent of the gliomas evaluated provided adequate DNA from archival FFPE tissue blocks. After applying the 2021 WHO diagnostic criteria the initial morphologic diagnosis changed for 35% (18/52) of cases. Diagnoses of 5 (9.6%) gliomas were upgraded, and 7 (14%) were downgraded. Conclusions This study shows that the incorporation of molecular testing can considerably improve brain tumor diagnoses in Nigeria. Furthermore, this study highlights the diagnostic challenges in resource-limited settings and what is at stake in the global disparities of brain tumor diagnosis.

Abstract BACKGROUND The diagnosis and management of patients with brain tumors currently uses WHO defined morphologic and molecular features. However, neuro-oncology practice in low resource settings relies on histomorphology. This study aims to reclassify glioma cases diagnosed in the Department of Anatomic and Molecular Pathology Lagos University Teaching Hospital using the 2021 WHO classification. METHODS Fifty-six cases of glioma diagnosed between 2013 to 2021 were evaluated. Morphologic diagnosis was reassessed. Five-micron sections were obtained for immunohistochemistry (IHC), and genetic testing (DNA and RNA); after manual macrodissection for tumor enrichment using 10μm sections. IHC for IDH1-R132H, ATRX, BRAFV600E, P53,Ki67, and H3K27M and OncoScan chromosomal microarray analysis were performed. NGS mutation/fusion analysis and EPIC methylation array profiling are in progress. RESULTS Of 56 cases evaluated, median age was 22 years (range=1-60 years); 71% were males. The initial morphologic diagnosis include 21 pilocytic astrocytoma, 11 glioblastoma, 9 ependymoma, 7 diffuse astrocytoma, 3 anaplastic astrocytoma, 2 high-grade gliomas, 1 oligodendroglioma, 1 diffuse midline glioma, and 1 pleomorphic xanthoastrocytoma (PXA). Histomorphologic re-evaluation revealed discordant diagnosis in 29% (16/56) of cases. Of the 56 cases, 73% (41/56) had usable DNA yield and 38% (21/56) had DNA yield of ≥ 750ng. Chromosomal microarray analysis was completed for 50% (28/56) cases. The revised 2021 WHO diagnosis were: 5 glioblastoma, IDH-wildtype, 5 pilocytic astrocytoma, 4 glioma NEC, 3 posterior fossa ependymoma, group B, 3 PXAs, 3 astrocytoma, IDH-mutant, 2 pediatric low-grade glioma, 2 supratentorial ependymoma, ZFTA fusion-positive, 1 posterior fossa ependymoma, group A. In 71% (20/28) of cases, diagnosis was revised using the 2021 WHO criteria. CONCLUSION Most cases had usable DNA yield. Overall, hsitologic re-evaluation and molecular testing based on the 2021 WHO classification guidelines refined the diagnosis in 48% (27/56) of cases.

Abstract BACKGROUND The diagnosis and management of patients with brain tumors currently uses WHO defined morphologic and molecular features. However, neuro-oncology practice in low resource settings relies solely on histomorphology. This study aims to reclassify glioma cases diagnosed in the Department of Anatomic and Molecular Pathology Lagos University Teaching Hospital using the WHO 2021 classification. METHODS Fifty-six cases of glioma diagnosed between 2013 to 2021 were evaluated. Morphologic diagnosis was reassessed. Five-micron sections were obtained for immunohistochemistry (IHC), and genetic testing (DNA and RNA) after manual macrodissection for tumor enrichment used 10-µm sections. IHC for IDH1-R132H, ATRX, BRAF-V600E, p53, Ki67 and H3-K27M and Oncoscan chromosomal microarray analysis were performed. NGS mutation/fusion analysis and EPIC methylation array profiling are in progress. RESULTS Of the 56 cases evaluated, median age was 22 years (range, 1-60); 71% were male. The initial morphologic diagnoses included 21 pilocytic astrocytoma, 11 glioblastoma, 9 ependymoma, 7 diffuse astrocytoma, 3 anaplastic astrocytoma, 2 high-grade gliomas, 1 oligodendroglioma, 1 diffuse midline glioma, and 1 pleomorphic xanthoastrocytoma (PXA). Histomorphologic re-evaluation revealed discordant diagnosis in 29% (16/56) of cases. Of the 56 cases, 73% (41/56) had usable DNA yield and 38% (21/56) had DNA yield of ≥750ng. Chromosomal microarray analysis was completed for 50% (28/56) cases. The revised WHO 2021 diagnosis was: 5 glioblastoma IDH-wildtype, 5 pilocytic astrocytoma, 4 glioma NEC, 3 posterior fossa ependymoma, group B, 3 PXA, 3 astrocytoma IDH-mutant, 2 pediatric low-grade gliomas, 2 supratentorial ependymoma, ZFTA fusion-positive, 1 posterior fossa ependymoma, group A. In 71% (20/28) of cases with molecular testing, diagnosis was revised using WHO 2021 criteria. CONCLUSION Most cases had usable DNA. Overall, histologic re-evaluation and molecular based on the WHO 2021 criteria refined the diagnosis in 48% (27/56) of cases.