Diagnostic aspects of pediatric embryonal tumors of the central nervous system: what should know pediatrician
Authors: Dinikina Yu. V. , Smirnova A. Yu. , Osipov N. N. , Spelnikov D. M. , Morgacheva D. A. , Zheludkova O. G. , Belogurova M. B. , Nikitina I. L. 
Published: October 2024

Background. Early identification of pediatric central nervous system (CNS) tumors is important in relation to disease prognosis, as well as long-term treatment outcomes, which determine subsequent quality of life. The predominance of embryonal tumors (ETs) in early childhood actualizes the problem of timely verification of the diagnosis. Factors contributing to the extension of diagnostic time in the presented patient’s cohort include the inability to adequately verbalize complaints in young children, a wide range of clinical presentations, including nonspecific ones, the relatively low incidence of ET in the population and the low level of oncological alertness among specialists. This determines the need for a more careful assessment of the clinical manifestations and disease-associated symptoms by doctors of all specialties and, especially, primary care specialists. Aim. Analysis of clinical symptoms at the disease’s onset in pediatric CNS ET in order to determine their associations with the tumor’s characteristics (site, hystologic type) and the patient’s features. Materials and methods. A retrospective analysis of data from 124 pediatric patients with CNS ET who received treatment from 2010 to 2023 in the departments of pediatric oncology of the Almazov National Medical Research Center and the St. Petersburg Scientific Research Center for Medical Sciences (o) named after. N. P. Napalkov. The analyzed parameters were the age of manifestation, initial symptoms, duration of the anamnesis and the period before verification of the diagnosis, localization and histological type of tumors. For statistical analysis, Fisher’s exact test, modified Pearson test, Kruskal-Wallis and Mann-Whitney tests, as well as (to assess the duration of anamnesis) the Cox model were used. Results. The most common type of CNS ET in the study group was medulloblastoma (MB; 66.1%). The average age of patients, in general, was 61 months, boys predominated (58%). The median age varied depending on the histological tumor type: the maximum was 72 months in patients with medulloblastoma and the minimum was 9 months in children with atypical teratoid rhabdoid tumor (ATRT). Both medians are significantly different from the total median (29 months) of all other tumors (p = 6.53 ∙ 10-4 and p = 0.029, respectively). The most frequent symptoms in patients with ET were nausea and vomiting (68%), headache (50%), and gait disturbances (25.6%). Increased head circumference/bulging fontanel (p = 0.0016) and torticollis (p = 0.0057) were the most common symptoms associated with younger age. Headache (p = 1.30 ∙ 10-9), nausea and vomiting (p = 0.019), diplopia (p = 0.0057), weight loss (p = 0.017) and dizziness (p = 0.013) were associated with older age. Headache was predominated symptom in medulloblastoma (p = 2.60 ∙ 10-4) compared to other ETs, and less common in ATRT (p = 1.51 ∙ 10-4), which may be due to the patient’s age. Fontanel bulging in medulloblastoma, unlike other ET, was not observed, which is also associated with age. Seizures were observed in all cases of CNS neuroblastoma - significantly more often (p = 0.034) than in other ETs. The most common tumor location was the posterior cranial fossa (PCF) (83.6%). PCF localization was associated with headache (p = 0.05, borderline significance) and nausea/vomiting (p = 0.040). Parietal localization was associated with seizures (p = 0.041). Four patients in the cohort had asymptomatic disease’s manifestations. The diagnosis was established by a routine screening examination. The absence of symptoms was associated with location outside the PCF (p = 0.011) and with younger age (p = 0.053, borderline significance). The diagnosis was established in a significantly shorter time if children had symptoms such as nausea and vomiting (p=0.0017), paresis and paralysis (p=0.0059). Conclusion. In patients with CNS ETs, statistically significant relationships are revealed between age, histological type, tumor site and certain symptoms. Nevertheless, the absence of strictly specific clinical manifestation determines the indications for a careful assessment of the pediatric somatic and neurological status and timely neuroimaging in children when even potential symptoms typical for CNS tumors are identified.