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Embryonal tumor with multilayered rosettes (ETMR) is a rare, aggressive pediatric CNS embryonal tumor, now defined molecularly by C19MC amplification on chromosome 19q13.42.
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Key characteristics:
| Feature | Details |
|---|---|
| WHO Grade | Grade IV (high-grade malignant) |
| Typical Age | Infants and toddlers (<4 years) |
| Sex | Slight female predominance |
| Common Location | Supratentorial hemispheres > brainstem > cerebellum |
| Growth Pattern | Rapid, infiltrative |
| Prognosis | Very poor despite aggressive therapy |
https://doi.org/10.1038/s43018-025-00964-9
| Marker | Description |
|---|---|
| C19MC amplification | Diagnostic hallmark (~90% of cases) |
| LIN28A positivity | Reliable immunohistochemical surrogate |
| DICER1 mutations | In rare ETMRs without C19MC alteration |
| TERT activation, TP53 alterations | Sometimes seen, linked to poor prognosis |
| Feature | Description |
|---|---|
| Multilayered (ependymoblastic) rosettes | Characteristic finding: small round blue cells around central lumina in multilayers |
| Neuropil-rich areas | Scattered islands of differentiated neuronal tissue |
| High mitotic activity | Reflects aggressiveness |
| Immunohistochemistry | LIN28A+, synaptophysin+, Ki-67 high (>50%), GFAP−/variable |
Histopathology showed a H&E × 10: biphasic histologic pattern: areas of small embryonal cells with multilayered rosettes and paucicellular fibrillar areas. b H&E × 40: multilayered rosettes consisting of pseudostratified neuroepithelium with a central round lumen. Immunohistochemistry × 40: the neuropil-like areas show positive expression for synaptophysin (c) and vimentin (d). Tumor cells are negative for cytokeratin (e)
Bouali, S., Zehani, A., Mahmoud, M. et al. Embryonal tumor with multilayered rosettes: illustrative case and review of the literature. Childs Nerv Syst 34, 2361–2369 (2018). https://doi.org/10.1007/s00381-018-3972-x
| Imaging Feature | Description |
|---|---|
| T1 | Hypointense mass, often with areas of hemorrhage or necrosis |
| T2/FLAIR | Heterogeneous signal, surrounding edema |
| DWI | Restricted diffusion due to high cellularity |
| T1+C | Variable but often strong enhancement |
| Calcification | Frequently seen on CT |
| Mass effect & hydrocephalus | Common, especially with large supratentorial lesions |
Supratentorial lesion:
Preoperative magnetic resonance imaging (MRI). Axial precontrast T1-weighted images show a huge and well-circumscribed mass in the right parieto-occipital region, which is hypointense to adjacent brain in most parts (a). The cerebral falx clearly shifts to the left. Axial (b) and coronal (f) T2-weighted image shows mass with mixed signal intensity, including iso- and hyperintense signal. Apparent vascular edema is present in surrounding area. Axial postcontrast T1-weighted images show the mass with minimal inhomogeneous contrast enhancement (c). Fluid-attenuated inversion recovery sequence reveals mild hyperintensity (d) and lesion shows no diffusion restriction (e)
Bouali, S., Zehani, A., Mahmoud, M. et al. Embryonal tumor with multilayered rosettes: illustrative case and review of the literature. Childs Nerv Syst 34, 2361–2369 (2018). https://doi.org/10.1007/s00381-018-3972-x
Brainstem lesion:
MRI for ETMRs, (A) TIWI showed a hypointense mass in the brainstem, which was hyperintense on both T2WI (B) and DWI (C) (blue arrows, case 5); (D) a 3×2×1 mass in the left parietal and occipital lobes with ringlike contrast enhancement (blue arrow, case 6).
Xu K, Sun Z, Wang L, Guan W. Embryonal tumors with multilayered rosettes, C19MC-altered or not elsewhere classified: Clinicopathological characteristics, prognostic factors, and outcomes of 17 children from 2018 to 2022. Frontiers in Oncology. 2022;12. doi:https://doi.org/10.3389/fonc.2022.1001959