The authors reported a retrospective series of pediatric central nervous system tumors diagnosed at a tertiary oncology centre in North India from January 2019 to December 2024. Ninety-two tumors were included. The cohort showed a male-to-female ratio of 2.5:1. The study team extracted demographic details, tumor site, histopathology, immunohistochemistry findings, and assigned WHO CNS 2021 grades from electronic medical records. Ethics approval was obtained and informed consent was waived by the institutional ethics committee for this retrospective analysis.
Embryonal neoplasms formed the single largest diagnostic group, representing 38.02% of cases. The investigators recorded medulloblastoma as the predominant embryonal tumor, comprising 88.57% of embryonal lesions reported. Astrocytic tumors comprised 31.52% of the series, while ependymal tumors accounted for 23.91%. Other tumour types were less frequent but included germinomas and a spectrum of solitary entities such as rhabdoid meningioma and hemangioblastoma.
Grade distribution skewed toward high-grade disease in this cohort. The study team reported that grade 4 tumors were the most frequent (48%), grade 3 comprised 27%, grade 1 made up 17%, and grade 2 accounted for 8% of tumours. These proportions reflect the high representation of embryonal and other high-grade tumours in the sample.
The authors described targeted use of immunohistochemical surrogate markers to permit integrated classification aligned with WHO CNS 2021 recommendations. Molecular subgrouping was performed on seven medulloblastomas: five were categorized as non-WNT/non-SHH by immunophenotype, one as SHH-activated TP53-wild-type, and one as SHH-activated TP53-mutant, according to the reported IHC surrogates. The source did not provide additional technical details on antibodies, thresholds, or complete molecular assays beyond immunohistochemical surrogate use.
Ependymoma classification used immunomarkers to define molecularly distinct entities when feasible. Ten ependymomas were classified: all eight supratentorial tumours showed L1CAM positivity consistent with ZFTA fusion-positive ependymoma, while the two posterior fossa tumours were identified as posterior fossa group A (PFA) ependymomas based on the study team's IHC-based approach. The authors noted that incorporation of immunohistochemistry allowed integrated histomolecular diagnosis for several tumours in this resource-constrained setting.
Tumor topography in the series was concentrated in the posterior fossa, which was the single most common site at 51%. Cerebral hemispheres were the next most frequent location at 37%. Less common sites included the spinal region (5%), sellar region (2%), pineal region (2%), and hypothalamus (1%). The cohort included two germinomas and single cases of atypical choroid plexus papilloma, adamantinomatous craniopharyngioma, and rhabdoid meningioma, each described in the study abstract.
The study team emphasized that use of immunohistochemistry facilitated WHO CNS 2021-aligned classification in multiple cases, enabling molecular subgroup assignment without reporting the full extent of molecular testing. The authors compared their tumor spectrum with contemporary Indian and Western series and reported comparability.
This analysis was retrospective and single-centre; those design features limit generalisability beyond the institution's referral patterns. The source did not report detailed methodology for the immunohistochemical assays (for example, specific antibodies, scoring criteria, or validation against molecular gold-standard tests), nor did it provide individual case-level survival or outcome data. Those elements remain unreported in the abstract and are therefore not available for clinical interpretation from this source.
Specific unanswered clinical questions documented by the authors include how best to operationalize integrated histomolecular diagnosis broadly in resource-limited settings and which immunohistochemical surrogates provide sufficient fidelity compared with molecular assays; the study notes the increasing importance of integrated diagnosis but does not provide standardized laboratory workflows or cost-effectiveness data. Future work should address assay standardization, prospective validation against molecular platforms, and linkage of integrated diagnoses to clinical outcomes in regional cohorts.