Lachance, Daniel Honore

AbstractBackgroundCrystal‐storing histiocytosis (CSH) is a rare form of histiocytosis with intralysosomal accumulations of immunoglobulins or paraproteins that aggregate as crystals. Central nervous system (CNS) involvement of CSH is uncommon but should be considered in cases of persistent parenchymal enhancement on neuroimaging.MethodsWe describe one local case of CNS CSH and 10 additional cases identified by literature review.ResultsAmong 11 CSH patients, lesions involved either the dura (2/11) or brain parenchyma (9/11). Two cases had leptomeningeal enhancement. One case had spinal cord involvement. Two cases were associated with marginal zone lymphoma; one case was associated with an immunoglobulin A‐plasma cell dyscrasia. Eight of 11 cases had outcome data available: 7/8 cases had clinical and/or radiological improvement and 1/8 had radiological stability.ConclusionsCentral nervous system involvement of CSH is rare. Potential cases should be comprehensively evaluated for lymphoma or myeloma with positron emission tomography/computed tomography (CT) of the body or alternatively, CT of the chest, abdomen, pelvis and nuclear bone scan, bone marrow biopsy, serum protein electrophoresis, and cerebrospinal fluid protein electrophoresis. Treatment is targeted toward the underlying malignancy.

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 Diffuse hemispheric glioma (DHG) is an uncommon infiltrating glioma, defined in the World Health Organization 2021 guidelines by a mutation in the H3F3A gene at codon 34 (H3.G34). DHG primarily affects children and young adults. Due to its rarity, there is paucity of knowledge regarding factors affecting overall survival (OS). We retrospectively assessed our institutional experience and present a review of the literature. METHODS We searched our institution’s pathology records to identify six cases of DHG. Demographic, clinical, diagnostic, treatment, and outcome data were recorded. We next searched for published articles regarding DHG cases via PubMed through May 2023. Four-hundred-fifty-four published individual cases of H3.G34 glioma were identified, 204 of which were hemispheric/supratentorial tumors with OS data reported, providing a combined 210 cases for analysis. 132 of these cases included MGMT promoter methylation status. 111 included extent of surgical resection. Kaplan-Meier and Cox regression survival analysis was performed. RESULTS Age range for DHG patients was 7-66 years (median 17). Median OS was 18.5 months (95% CI, 17-25). Greater extent of surgical resection and presence of MGMT promoter methylation were associated with better prognosis. Median OS for biopsy alone was 12 months (95% CI, 10-NA), subtotal resection was 16 months (95% CI, 14-23), and gross total resection was 27 months (95% CI 23-NA) – log-rank p< 0.001. OS for MGMT promoter unmethylated was 14 months (95% CI 12-22), MGMT promoter methylated was 24 months (95% CI, 17-30) – log-rank p=0.028. Contrary to previous reports, patient age was not found to impact prognosis (using 18, 21, and 40 years as cutoffs or as a continuous variable with Cox regression). CONCLUSION Extent of surgical resection and MGMT promoter methylation status are important prognostic factors for DHG. Unlike many primary brain tumors, survival does not appear to be significantly impacted by age.