Clinicopathological and prognostic insights into Embryonal Tumors with Multilayered Rosettes (ETMRs)

Embryonal tumors with multilayered rosettes (ETMRs) are rare, highly aggressive pediatric brain neoplasms characterized by early onset and dismal prognosis. This study presents a comprehensive clinicopathological and molecular analysis of ETMR cases diagnosed over a 14-year period at National Cancer Institute, Cairo University, with a focus on diagnostic features, clinical presentation, and survival outcomes. A retrospective review of 35 patients with histopathologically confirmed ETMRs was conducted. Demographic data, clinical symptoms, neuroimaging findings, histopathologic features-including rosette formation, mitotic activity, necrosis, and Ki67 proliferation index-as well as molecular analyses for C19MC amplification and LIN28A expression were evaluated. Kaplan-Meier survival curves and univariable Cox regression were used to assess prognostic associations. The cohort comprised 17 females and 18 males, with a median age of 36 months. Common presenting symptoms included signs of raised intracranial pressure, seizures, and motor deficits. Gross total resection was achieved in 43% of patients, and 48% received adjuvant chemoradiotherapy.Histopathologic examination consistently revealed ependymoblastic rosettes (true multilayered rosettes) and high mitotic activity. LIN28A was diffusely expressed in all assessable cases. Molecular confirmation by PCR testing was done in 20 cases. The median overall survival was 19 months. Factors associated with inferior survival included incomplete surgical resection, absence of adjuvant therapy, and presence of necrosis and high mitotic index. ETMRs demonstrate consistent histological and immunohistochemical features that can guide diagnosis in resource-limited settings. Despite therapeutic advances, prognosis remains poor, underscoring the urgent need for novel therapeutic strategies. Molecular testing for C19MC amplification and LIN28A expression supports diagnostic confirmation and may hold future prognostic or therapeutic relevance.